igoi] Charron — Fat in the Animal Body. 137 



There is no difficulty for anyone in admitting that the fat of 

 the body 7nay be derived from the ready formed fat absorbed as 

 food. But is that the only source of fat ? 



In 1742 Beccaria, in Bologna, advanced the idea that animals 

 take the substances which form their tissues ready made from the 

 vegetable kingdom. This theory was supported by many prom- 

 inent men, amongst whom may be mentioned Prout, in England, 

 and Dumas, in France. The chief point of the theory was that 

 animal fat is derived from the fat of plants. This appeared 

 so simple and probable, that for a long time nobody questioned 

 its truth. Liebig was the first (in 1848) to dispute this deep seated 

 belief of over one century old. He observed that if by lack of 

 exercise or otherwise, respiration is hindered in Herbivora, fat 

 deposits in greater quantity and thence he argued that as there 

 was no more fat absorbed in the food than previously, that greater 

 deposition must be due to the formation of new fat from the 

 fat free substance of the food. Hindering respiration he thought 

 diminished the combustion of the carbohydrates and the protein, 

 the unburnt carbon was retained in the body and used up in the 

 formation of fat. 



As a natural consequence Dumas and Liebig entered into an 

 active controversy, and this set them and their supporters at work 

 experimenting to discover additional proofs to uphold their respec- 

 tive pretentions. Milne Edwards sided with Dumas. 



It is not my intention to give you an account of all the experi- 

 ments undertaken. A few will suffice to make the results and the 

 conclusions drawn therefrom clear to your mind. 



Upon instituting experiments it occurred to Voit that fat 

 might possibly be formed from protein. He had noticed that 

 adipocere is often formed from nitrogenous tissue, muscles, etc., 

 when portions of the animal body are kept underwater. Wishmg 

 to ascertain whether really albumin could be changed into fat, he 

 kept glass tubes, containing pieces of meat, in a water bath at a 

 constant temperature of 40^0. for 3^^ months. At the end of this 

 time he found a small increase in the fat content of the substance. 

 The increase was small, but nevertheless the fact was established 

 that fat could be formed from protein substances. Further investi- 



