What was gelatin originally used for?

Children, collect bones!


In the 19th and early 20th centuries, bones were an indispensable, largely import-dependent raw material of the chemical industry, which used them to produce fertilizers, animal feed, glue, gelatine, soap and other products. The topic of bone recycling was used in school lessons during the Nazi era to make young people aware of the relevance of the four-year plan and the German policy of self-sufficiency and to motivate them to participate in the domestic collection of this raw material as part of the waste material collections. Various NS authorities had developed a differentiated spectrum of teaching materials to support the treatment of this topic in schools. The article examines the messages conveyed by these, at the time, ultra-modern teaching media and shows how subjects that seem less prone to ideology, such as chemistry classes, were politically instrumentalized.


In the nineteenth and early twentieth centuries bones were an essential raw material for the German chemical industry, vital to the production of fertilizer, glue, gelatine, soap and other products. As most of this material was imported, the German school system during the “Third Reich” took the utilization of bones as an example to illustrate the relevance of the four-year plan of 1936 and its policy of economic self-sufficiency. The school children were encouraged to collect bones from domestic sources and bring them to the collecting points in the schools. Several NS-institutions developed a variety of teaching aids and materials to support school education on this economically and politically important topic. Focussing on the example of bone utilization, this paper examines the messages and intentions of these educational materials. It also demonstrates how even apparently ideologically unbiased school subjects, such as chemistry, were instrumentalized for the political indoctrination of the pupils.

School lessons during the Nazi era and the ideologization of education and upbringing have been researched for decades.Footnote 1 In the meantime, there are not only works on individual school types and forms, but also on individual subjects, whereby the interest initially concentrated on the strongly ideological subjects of German, history, geography and, in the natural sciences, biology (Weiss 1994; Bäumer-Schleinkofer 1995) . But there are also initial studies of physics and chemistry classes, which seem less prone to ideology (Brämer & Kremer 1980; Stoya 2002). This essay deals with a detailed aspect of school lessons in the time of the “Third Reich”: the numerous teaching materials on the subject of bone utilization that have been handed down. Various school books, but above all the teaching boards popular at the time,Footnote 2 Student worksheets, series of slides and educational films show how intensively and with multimedia this topic has been treated since 1937. Since these meanwhile uncommon means of visualization are now kept in museums and special collections, they have not yet been taken into account by historical research. The requisition and recycling of old materials, which was practiced not only by the German Reich and its allies, but also by the Allies and the neutral states during the Nazi era,Footnote 3 The approach pursued here of analyzing the diversity of these teaching materials against the background of the economic importance of the raw material bones gives it new facets and sharper contours. In the following, the relevance of the bone collections imposed on the students for the German autarchy and armaments policy is presented and it is shown how these activities were accompanied and supported by school lessons with the help of various teaching and propaganda materials; Then the (wartime) economic importance of various products is discussed which were manufactured in the “Third Reich” from the so far hardly recognized industrial raw material bones.

In order to establish a uniform National Socialist education system, the Reich Ministry for Science, Education and National Education was created in 1934, known as the Reich Ministry of Education for short (Nagel 2012). When it was founded, for the first time in the history of German schools, a central government body was responsible for educational policy. The school-political activities of the new ministry did not consolidate until 1937, when new curricula for the individual school types gradually appeared across the country (Stoya 2002: 26 f.). A few months earlier, in autumn 1936, the four-year plan, which was important for Nazi economic policy and which was to have a lasting impact on the teaching content at schools, had been announced (Anonymous 1937; Hartmann 1938; Wolter 1938). Within four years, the German economy was to become largely independent of foreign imports and thus ready for war. Since the First World War had shown how vulnerable the resource-poor German Reich, which was dependent on raw material imports, was in the event of war, the Nazi state pursued a dedicated policy of self-sufficiency. Business and industry were asked to limit the use of import-dependent raw materials to the bare essentials and, if possible, to use substitutes from domestic resources. In order to make it clear to the young people that the implementation of the four-year plan also required them to undertake new duties, Germany's supply of raw materials has been dealt with in schools in many subjects since 1937, regardless of the type of school and grade, especially chemistry classes (Stoya 2002: 13 f.)

The four-year plan in class

The work published by the Reich Ministry of Education in 1938 Education and teaching in high school attested that chemistry lessons were of great "educational value", above all because of the school trials and visits to chemical plants organized by the school. The ministry demanded that chemistry classes arouse interest in economic issues and at the same time convey that science and technology ensure the “economic and cultural high standard” of the German people; it should show how the scientific and technical chemistry of the German industry made "new valuable raw materials from local materials" available, educate the youth to be economical in dealing with the materials available in Germany and contribute "to the understanding of contemporary issues". He also had to make it clear what a central role chemistry played in securing nutrition and the defense capabilities of the Reich (Education and Teaching in the Higher School 1938: 165–172). The chemistry books of that time show that these ideas were implemented through an increased focus of the learning content on national and economic aspects. The treatment of German chemical history (Bäumer-Schleinkofer 1994), defense chemistry and the raw material situation in the Reich are evidence of this policy (Beier 1934; Gölz & Jansen 1990; Gölz & Jansen 1993). The data contained in the school books on the German domestic and foreign production of certain raw materials repeatedly drew the pupils' attention to the four-year plan. Since co-education was rejected in the Nazi state and the girls' schools were supposed to prepare their pupils for their future tasks as housewives and mothers by focusing more on the nutritional and domestic aspects of chemistry, the treatment of military chemistry and certain facets of the four-year chemistry plan is mainly in the school books Schools for boys, especially those for the mathematical and scientific branch (Dörmer & Dörmer 1939). This type of school allowed science classes (physics and chemistry) more hours per week (three hours from grades 10 to 13) than girls' schools (three hours in grades 10 and 12) or classic grammar schools (two hours in grade 10) and therefore allowed one more intensive treatment of the subject matter (education and instruction in secondary schools 1938: 25–31; Stoya 2002: 5).

During the Nazi era, experimental lessons were of particular importance because they trained dexterity, observation, conscientiousness, cleanliness, a sense of order and the ability to precisely complete a task and thus trained skills that were also useful for military training. Topics relevant to the four-year plan were therefore often dealt with in school trials (Education and Teaching in Higher Schools 1938: 166f .; Stoya 2002: 154–168). Usually, the student experiments took place within the framework of the scientific and mathematical working groups introduced by the Reich Ministry of Education, which offered committed teachers in addition to compulsory lessons. On the one hand, the experiments were intended to introduce the young people to scientific research practice, but at the same time to be "realistic", "practically usable" and "useful for the community" (Education and Teaching in the Higher School 1938: 3; 204-206). In order to make it easier for teachers to organize experimental lessons, many books with experiments on defense and four-year plan chemistry were published in the late 1930s.Footnote 4 One of them should be highlighted here because it contained, among other things, experiments on the subject of bone utilization: the School trials with German raw materialscompiled by Walter Haferkorn, who works at the University for Teacher Training in Leipzig (Haferkorn 1938). In addition, he and his colleague Herbert Priemer had designed a series of multi-colored school murals consisting of 31 panels, which was published by the same publisher as the book (Haferkorn & Priemer 1937–1939). With these coordinated teaching materials, all raw materials relevant to the four-year plan could be dealt with in the classroom. The panels mainly illustrated the processes involved in the production and processing of a particular raw material. The first picture in the series appeared in May 1937 and dealt with the raw material bones and their utilization (see Fig. 1). Suitable bone experiments (Kahn 1923/24; Pröbsting 1936; Hessenland 1938: 71–73) were also in the first place in Haferkorn's experiment book.Footnote 5 A brochure with relevant experiments for elementary school (Garz 1939) as well as the publication of further bone experiments in the renowned Lesson sheets for math and science (Zeitler 1940) show how much the educators tried to treat this topic experimentally.

Bone collections

To classify these findings, the precarious raw material situation in the empire and the importance of the raw material bones must be discussed. During the First World War, the German Reich had already pursued three strategies to compensate for the lack of raw materials due to the British naval blockade: thrift in dealing with scarce materials, switching to substitutes that could be synthesized from domestic resources and the fullest possible use of all waste that could be recorded inland - and waste materials. These strategies were once again of great importance during the Nazi era, especially the latter with regard to bones. As early as 1934, the Nazi regime began to expand the existing structures for recycling used materials and waste: Rubber, asbestos, leather, textile and wood waste, waste oil, waste paper, scrap metal, glass and other recyclable materials were collected and recycled as separately as possible fed. As in the First World War, household waste, including kitchen waste, was a valuable domestic resource in the “Third Reich”, from which everything that could be used, including bones, was to be sorted out. In order to explain the war importance of this raw material, which had already been collected by housewives and schoolchildren in 1917/18, the Image and Film Office (Bufa) founded by the Supreme Army Command had a short film with the title in 1918 Collect bones produced.Footnote 6 Hermann Göring took up these measures again twenty years later in his function as the representative for the four-year plan. In order to prevent the German Reich from going into a war as unprepared as in 1914, the National Socialist state prepared itself for a war case from a long time ago and therefore created an institution as early as 1937 to organize the recycling of waste materials: the Reich Commissioner for Recycling of old materials. Statistical surveys had shown that only about a fifth of the bones produced in the empire were used industrially; over 70 percent were lost because they were not collected (Wimmer 1937: 5 f .; Gerhardt & Höfner 1942: 34–36). However, since the bones caught by the scrap trade did not meet the industrial needs, additional material had to be imported from abroad every year. In order to save or at least reduce foreign exchange expenses for these imports, from 1937 onwards, in addition to bone waste from cover shops, slaughterhouses, butchers and the meat industry, those from private households, company canteens and restaurants that had previously disappeared unused in the garbage should be collected. According to model calculations, the requisition of these small quantities should pay off (Ziegelmayer 1936: 136; Ziegelmayer: 1941: 196). Extrapolated to the total number of households, they represented “millions” according to Nazi propaganda (Köstering 2003). In contrast to the First World War, however, bone collection was no longer primarily left to the housewives, but rather placed on the schoolchildren, whereby it was speculated that the children would also motivate the mothers (Anonymous 1942j). On the basis of these considerations, a decree published by the Reich Ministry of Education in January 1937 asked the pupils to hand in the waste bones that had accumulated in households at school. After the turning points of 1936 (announcement of the four-year plan) and 1937 (beginning of the school-based bone collection), the outbreak of war in 1939 represented the third turning point in the history of raw materials collection by the students the "Aryanization" of the scrap dealerships, which were often in "Jewish" possession, had been lost, but also filled the gaps that arose after the start of the war through the drafts. From the autumn of 1939 onwards, bone collections rested almost exclusively on the shoulders of young people who collected them free of charge. The fact that the Hitler Youth (HJ) and the Sturmabteilung (SA) repeatedly took part in shock actions did nothing to change the fundamental redistribution of burdens (Miller 2014: 36–38).

Bonus system

Since its establishment, the Reich Commissioner for the Recycling of Used Materials has drawn attention to the relevance of the waste material collections with lectures, press articles, appeals, films, radio broadcasts and brochures (Hertenstein 1939: 280). After the start of the war, advertising activities were intensified. A wall calendar distributed free of charge reminded the mothers and school-age children to hand over the bones to the schoolchildren who were designated as the “waste material supervisor” or to the school’s “waste material teacher” on the collection days.Footnote 7 There the material was weighed and the result documented. Then the bones were put in a container that was regularly emptied by a scrap dealer. Many teachers had reservations about the fact that the school was being misused as a collection point for the professional trade in used materials (Krause 1943). Educators loyal to the regime justified this as follows:

It [the bone collection] causes inconvenience for teachers and students [...]. It may also cost time that is lost in class. But it would be absolutely wrong to complain about it. It is not something alien to school, but a measure that is an essential part of current school education. Or do you perhaps think that you have done more when arithmetic problems and other teachings alone have “worked through” the necessity of collecting bones without actually practicing it? Opinions are divided here: one still thinks entirely in terms of purely formal education; the other knows that education can only be fruitful if it is integrated into political upbringing (Schwierskott 1938: 551–552).

The bone collections became economically more important after the start of the war,Footnote 8 because the material deliveries from overseas were canceled. Since February 1940, the pupils had to collect all other waste and waste materials that accumulated in the household, in addition to bones. In 1941, the Reich Commissioner for Scrap Recycling created a system of points and rewards that marked the fourth and final turning point in the history of the collection of recyclable materials in schools. Since that year, the "scrap teacher" has given individual pupils or classes credit points for the delivery of a certain amount of a specific scrap. With this approach, it became obvious whether and to what extent the expected minimum quantities had been met.Since a kilo of bone was relatively easy to collect, while it was considerably more difficult to collect the same weight of rags, the transfer of one kilo of used textiles was given the highest five points; Then came the bones, rated relatively high with three points, which counted as much as non-ferrous metal; with two points, the waste paper was in third place; In contrast, there was only one point for a kilo of scrap iron (Steinberg 2008: 50 f .; Brockmann 1994: 121 f .; Sagemüller 1994: 232). If a certain number of points was reached, there was a bonus, for example a handwritten Göring picture or a certificate. But there were also prizes such as pocket calendars, pencils,Footnote 9 Books, globes, compass boxesFootnote 10 or books with political content distributed (Wüstenfeld 2002: 29; Barwich 2003: 38 f.). The richest schools received a sculpture by the sculptor Walter Lerche, the boys 'schools a football player, the girls' schools a girl's head (Anonymous 1942). The most prestigious awards for individual students were radio equipment (Anonymous 1943d) or a three-day trip to Berlin, during which, if possible, a meeting with Göring was arranged. Successful "scrap teachers" received an "artistically valuable" certificate with the handwritten signature of the Reich Commissioner (anonymous 1943d). In fact, the recorded amounts of bones could be increased continuously from 1937 to 1944, despite the meat rationing introduced at the outbreak of war (Nadolni 1944) and despite the fact that even in 1943 not all larger businesses (hospitals, restaurants and catering establishments) were in the collections involved (Anonymous 1943a). Since 1944, however, the results have declined due to the deteriorating supply situation, which led to an adjustment of the bonus system: for five kilos of collective bones, which could also be delivered in pounds, one received a voucher that entitles them to buy a bar of curd soap - one in view of the Soap rationing attractive reward.Footnote 11 Even a few months before the end of the war, the Reich Ministry of Education took the school bone collections so seriously that it exempted schools that had closed due to the war from collecting waste materials at the end of January 1945; those who were able to keep teaching were obliged to compensate for these failures by collecting all the more diligently (Reichsminister for Science, Education and Public Education 1945: 14).

Teaching aids for elementary school

In order to explain the meaning and purpose of the bone collections to the children, the topic of bone utilization was dealt with several times in school, starting in elementary school. The NBC shooters were called in to collect bones, despite the concerns expressed by some parents about possible health problems: in fact, the collection points were unsanitary places where it stank (Teweleit 1993: 43 f .; Vorländer 2000: 49) and even came to rat plagues.Footnote 12 The Reich Committee for Economic Enlightenment (RVA), an institution subordinate to the Reich Propaganda Ministry, which, among other things, was supposed to promote the recycling of “German raw materials”, had a teaching board illustrated for children in 1939 with the request “We collect bones! We're helping to build Germany! ”(Meyer 1939). It showed a family tree of the most important products that can be made from bones and was supposed to be hung in the classroom or on the school staircase in order to constantly remind the little ones that, in the face of the war, they “became increasingly involved in the interests of bone utilization” (Anonymous 1940). At the foot of the bone tree (see Fig. 2), a blond boy wearing short trousers was depicted, who was just throwing his bones into the collecting container. Behind him stood a blond girl waiting to do the same.

The composition of the picture suggests that it was mainly the boys who were responsible for collecting bones. Ideologically charged texts on the subject of “We collect bones!” Were also found in the primers of the ABC-Schützen, for example in the following reading book, in which, tellingly, boys were again the main actors:

How proud little Fritz marches to school every day with his satchel! [...] His mother gave him a bag. [...] He meets several schoolmates on the next street corner. They also carry bags of bones, because today is collection day. Who is the most diligent in collecting? [...] There is a big barrel in the school yard. Now the bones rumble into the dark belly. The other classes have also collected a lot, and tomorrow the school will report to the dealer: “The bin is full! It can be picked up! ”We can be proud that we can help the Führer through our diligent collecting (Facharbeitsgemeinschaft deutscher Erzieher 1940: 90).

Also the school magazine published by the NS-Lehrerbund (NSLB) and intended for first to fourth graders German youth castle urged the children several times to collect bones with verses, short reports and the relevant cover design. A title page from the winter of 1941/42 showed three boys - again only the male gender - weighing beef ribs, which, however, are unlikely to have come from household collections (see Fig. 3). Shortly after the start of the war, the RVA also had a color-illustrated brochure with the title for the target group of first to fourth graders We help too! published, in which the importance of material and energy-saving behavior as well as the collection of old materials and bones was pointed out in verse.Footnote 13

In the illustrated school magazine also published by the NSLB Help!, which was aimed at fifth to eighth graders, articles on the topic of collecting waste materials were not in the foreground, but have been interspersed again and again since 1937 (Anonymous 1937a; Büdingen 1938; Anonymous 1940b). After the outbreak of the war, the editorial team of the magazine published a four-page, illustrated teaching chart in cooperation with the Reich Commissioner for Scrap Material Recovery, which the teachers could use to address the topic of bone recovery in the middle school due to the lack of suitable school books that had been revised according to the new curriculum (Reichswaltung [around 1940]) .Footnote 14 He skillfully combined factual information with political indoctrination by providing facts about the possible uses of the bones, but also by pointing out the military importance of this raw material to the children to support the German war and armaments industry with their collections. Even in middle school arithmetic classes, the topic played a role. In the form of dressed-up word problems, the students were given numerical material on the utilization of bones in the German Reich, with which they had to solve everyday tasks of three sets (Schiffner 1944: 177 f.).Footnote 15 The political appropriation of arithmetic lessons was expressed here, as in other cases, in the choice of the example used as a hook (Metzner 1931; Dorner 1935). The children encountered the same numerical material again in non-fiction books that were on the lists of literature to be acquired by the school libraries published by the Reich Minister of Education (Weber 1999), such as Ungewitter Exploitation of the worthless (Ungewitter 1938: 153) and Lübkes The German raw material wonder (Lübke 1938: 522). The 1941 essay by a 13-year-old elementary school student on the subject of "How I help to implement the four-year plan" reflects how dutifully the teaching content, drummed in like a prayer wheel, was received:

The four-year plan is very important because we don't have any colonies from which we can get raw materials for our factories. We also don't have enough foreign money to buy raw materials from other countries, which is why Hermann Göring created the four-year plan on the orders of the Fuehrer. The four-year plan sets us the task of saving. This mainly applies to the housewife. In the past, when she had old bones, they were just tossed in the trash can. All of this must no longer happen today. Every bone must be collected.Footnote 16

Teaching aids for special schools

There was even a simplified bone utilization scheme for the special school (Anonymous 1938). Because the understanding of abstract terms could not be assumed for these students, it used only a few, descriptive terms and, in contrast to the blackboard, did not indicate the military significance of the bone collections for the NBC shooters. The technical terms glycerine and stearine, which are far too demanding for the target group, show that the scheme was not well thought out.Footnote 17 Although the special school pupils certainly did not correspond to the ideal of healthy, physically capable young people propagated at the time, they were regarded as "full" national comrades insofar as they were expected to participate in the school bone collections. This was particularly true of the war years, when the collection of scrap material was viewed as military service by the German school.Footnote 18 Significantly, a circular issued by the Reich Minister of Education in June 1941 once again called on all schools to collect waste materials (Reich Minister for Science, Education and National Education 1941), including the special schools, whose pupils were considered useful assistants for completing simple tasks (Kremer 2011: 167). In accordance with this logic of usefulness and in contradiction to the racial propaganda of the time, the “Jewish” schools also had to take part in the waste material collections (Anonymous 1942h: 114).Footnote 19 Various notes in the magazine published by the Nazi teachers' association The German special school prove that the special school students were quite successful at the bone collections and were often awarded.Footnote 20 In their naivety, they could be instrumentalized just as easily as garbage collectors like the elementary school students (Anonymous 1942b; Anonymous 1942c; Anonymous 1942e).

Teaching aids for high school

On the initiative of the Reich Commissioner for Scrap Recycling, another teaching board on the topic of bone recovery was published in 1938 (see Fig. 4), which, in contrast to the more process-oriented board designed by Haferkorn and Priemer (see Fig. 1), highlighted the intermediate and end products and therefore particularly suitable for chemistry and economics classes. The card was delivered with an explanatory booklet (Reich Commissioner for Scrap Recycling 1938a). Their acquisition was expressly recommended to schools by two decrees of the Reich Ministry of Education (Reich Minister for Science, Education and Public Education 1938, 1939). In addition, the Reich Commissioner had a slide series consisting of fifty recordings with the title The bone as a raw material and its utilization published, also with an accompanying booklet. The brief information on each photo resulted in a complete slide presentation (Reichskommissar für Altmaterialverwertung 1938b). The slides illustrated the technical processes involved in bone utilization and gave an idea of ​​the work in important bone processing companies. If the students could not be offered the most impressive form of illustration, a visit to a slaughterhouse or a fertilizer, glue, gelatine, candle or soap factory, this deficiency could be compensated for with a slide show.Footnote 21 The existence of the slide series shows once again the variety of visual, then highly modern media that were given to the teachers by various Nazi institutions in order to make the relevance of the bone collections clear to the students. However, neither the 1938 school chart nor the slide series were completely redesigned.

The way in which the order of magnitude of the bones processed in the German Reich was illustrated is clearly based on educational ideas from the film Collect bones (1918). There does not seem to have been a special educational film on the subject of bone utilization that was produced during the Nazi era. As the Reich Office for Educational Film (RfdU) founded by the Ministry of Education in 1934 and renamed the Reich Institute for Film and Image in Science and Education (RWU) in 1940, educational film played an important role in media education in the “Third Reich” (Niethammer 2016). Thanks to a requirement plan published in 1937 (a reaction to the inclusion of film in school lessons by decree) and the RWU directories, we know which films were planned or made specifically for chemistry and technology classes at that time (Weber 1937; Reichsanstalt für Film and Image in Science and Education 1940; Landesbildstelle Württemberg 1943; Kühn 1998: 267–308).Footnote 22 The fact that no new film on the subject of bone utilization was made in the “Third Reich” may have been due to the fact that Hanni Umlauf and her brother Walter had one on the main topic in 1937/38 Old material - raw material had produced.Footnote 23 This cine film, which was made on behalf of the Reich Commissioner for Scrap Recycling and the Reichsfrauenführung, also dealt with bone collection and recycling. Like its predecessor from 1918, it was primarily aimed at housewives as a "popular education" film. Since it had been expressly approved as an educational film by the test center in February 1938, it was also allowed to be shown in school.Footnote 24

Raw material bones

The efforts of the Nazi regime to record every waste bone in the Reich as far as possible require an explanation as to why this raw material was actually so sought after. Because of their particular chemical composition, bones are indeed a versatile and almost entirely usable raw material. When fresh, they consist of 50-60 percent inorganic matter, mainly calcium phosphate, calcium carbonate and magnesium phosphate (which made them a valuable source of calcium and phosphate), and about 30-40 percent organic matter, namely about 35 percent skeletal protein and 5-15 percent fat (making them a source of protein and, to a lesser extent, fat source). The rest is water. The ratio of the individual components to one another varies considerably depending on age, breed, nutritional status and the part of the animal from which the bones originate, even in the same animal species (Gerngross & Goebel 1933: 171–176; Ostertag et al. 1958: 364– 366).

As one of the first branches of the chemical industry to use waste as raw material, the bone processing industry emerged at the beginning of the 19th century (Fleck 1878: 6–84). The tar paint industry followed in 1857, using coal tar, the waste product of coking plants and coal gas factories. The phosphate-rich bones were initially processed exclusively into fertilizers, with the development of this branch of production initially originating in Great Britain (Wagner 1868: 607–616; 621–623). As the domestic raw material soon no longer met the demand, the British began to import bones from all over the world. In the 1820s they are even said to have ransacked the battlefields of the Wars of Liberation against Napoleon for bones and shipped them to Great Britain (Liebig 1861: 7; Vogel 1874: 45 f.). The need for phosphate fertilizers increased significantly after Liebig pointed out that phosphorus, nitrogen and potassium are essential for plant nutrition and must be returned to the soil after harvest to maintain its fertility. In order to meet the great demand, phosphate-containing ores were processed into fertilizers in addition to bones since the 1860s. However, these minerals had to be imported (Ost 1942: 385–396; Welsch 1981: 39 f.). In the 1880s it was discovered that the Thomas slag from steel production could also be used as a phosphate fertilizer in its ground form. Despite its extensive steel production, the German Reich was not self-sufficient even with this raw material, a classic industrial waste product (Welsch 1981: 79; 127 f.). When the German fertilizer industry was cut off from importing foreign phosphate ores during the First World War, it began to reflect on the use of domestic resources: the lean Lahn phosphates, which until then were not considered worthy of processing, as well as that, since the beginning of the 20th century, largely due to mineral fertilizers displaced bone meal. Knowing that thanks to the Haber-Bosch process, the German Reich was self-sufficient in the production of nitrate fertilizers, but partially relied on foreign raw materials for the production of phosphate fertilizers, the avoidance strategies pursued during the First World War were reactivated in the “Third Reich”: To in case of war To be able to process more domestic bones into phosphate fertilizers (and other urgently needed bone recovery products), the school bone collections initiated in 1937 created the infrastructure in good time before the occurrence of a specific crisis and shortage situation, which was necessary to record this important industrial raw material.

Since around 1848, the bones have been degreased before being ground into fertilizers.This not only improved the fertilizing effect; degreasing was also lucrative. The mixture of fatty acids produced when the bone fat is broken down can be converted into cheap soaps (core, lubricating, textile soaps)Footnote 25 or process into stearin candles; In addition, glycerine, a key product of chemical technology, was produced during fat breakdown. It was and is used in the manufacture of ointments, toothpastes and cosmetics as well as a textile finish. Because of its viscosity, it was and still is used as brake fluid (also in guns), mixed with water as an antifreeze (also in Wehrmacht vehicles) and as a plasticizer for films, ribbons, copier inks and printing inks. Since the invention of dynamite (nitroglycerin), however, the explosives industry, which is important for the war effort, has had the greatest need for glycerine. At the same time as the production of fat, the bone meal manufacturers began to process some of the defatted bones into charcoal by charring in the absence of air. It was used as a black pigment, for example for the production of shoe wax and paints, but also as medicinal charcoal; It was also of great importance as an adsorbent for industrial purposes.Footnote 26

Another milestone in the history of bone utilization was reached when the first factories were set up in France at the beginning of the 19th century and then also in Germany in the 1860s, in which the defatted bones were processed into glue and gelatine. In both cases it was a question of conversion products of the skeletal proteins contained in the bones, which were split under pressure with hot water. The process was controlled in such a way that the production of bone glue produced a product that sticks well and gelatine production produces a product that gels well (Bergmann 1919). Thanks to the increasing importance of photography in the second half of the 19th century and the rise of the photographic industry, gelatine manufacture developed into an important branch of industry, especially in the German Empire. Since the founding of the Agfa factory in Wolfen, it has owned the largest film factory in Europe and, after the Eastman-Kodak Company in the USA, the second largest in the world. Extremely high demands were made on the quality of the photo gelatine (Baier 1977: 261-280). Only a product made from low-fat, fresh slaughterhouse bones guaranteed durable, stain-free photos and films.Footnote 27 In a war situation, the availability of enough film material and photo paper, the production of which required photo gelatine in both cases, was essential for documentation and propaganda purposes. This also applied to other technically relevant types of gelatin, which were used, for example, as a finishing agent or tarnish protection for gas mask glasses. Equally important was edible gelatine, which the pharmaceutical industry needed to encapsulate drugs; But it was also processed into custard powder and used as a form-maker by the fish and meat canning industry.

In summary, it can be said that in the 19th century bones became the raw material basis for several branches of the chemical industry (Stohmann & Engler 1872: 386–398; Stohmann & Engler 1874: 652–674). The demand for this extremely versatile industrial raw material had already increased in the late 1870s to such an extent that even in the German Empire the demand could no longer be met from domestic resources, but only through additional bone imports from South America and India.

Critical analysis of the school murals

In the leaflet accompanying the Reichskommissar's teaching chart from 1938, it is claimed that between eighty and a hundred different products were made from substances obtained from bone recycling during the Nazi era (Reichskommissar für Altmaterialverwertung 1938a). The board showed that bones were not only used to make technically, agriculturally or militarily important products (drilling oils, putties, varnishes, printing inks, insulating, finishing, fertilizing, animal feed and plant protection products, glycerine, nitroglycerine), but also utensils ( Candles, typewriter tapes, shoe wax, copy paper, matches, furniture glue, medicines, shaving and skin creams) and luxury goods (artificial flowers, bone china). The wall chart, a pictorial icon that is repeatedly reproduced and also used as an exhibit,Footnote 28 conveyed the message that the bone collections contributed in many ways to safeguarding or even raising the standard of living and consumption of the German people.