248 FORMATION OF FAT BY ANIMALS. 



led them to regard it as, at all events to some extent, arising from the 

 albuminous constituents of the muscles being decomposed into fatty acids 

 and ammoniacal salts. Wagner, Donders, Burdach, and others, have fur- 

 nished many interesting experiments on the apparent transmutation of 

 various bodies, such as pieces of coagulated albumen, crystalline lenses, 

 etc., in the abdominal cavities of birds. These extraneous objects after a 

 time become enveloped in, and in some cases permeated by, fatty mate- 

 rial. But that this does not arise from metamorphosis of the protein 

 body introduced was well proved by the last observer, who employed 

 pieces of wood and the pith of elder with the same result. 



Whatever, therefore, may be the conclusion arrived at on the cases 

 The carnivora kere m * r duced whether, during a special metamorphosis, 

 find fat in their muscular tissue can pass into adipocire ; whether from fibrin 

 or starch, by the action of nitric acid, fats may be made, or 

 whether these substances pre-existed in the material from which they ap- 

 pear to arise, and are only disengaged or set free there can be no question 

 as regards one great group of animals, the carnivora, that they find in their 

 food a sufficiency of these hydrocarbons to meet all their wants. It is 

 as respects the other group, the herbivora, that this question of the arti- 

 ficial formation of fats from substances in which they did not pre-exist. 

 Do the herbiv an( ^ particularly fr m albumenoid bodies, becomes interest- 

 ora ever make ing. Do the herbivora find in their food all the fat they re- 

 quire, or are they obliged to fabricate a part ? 



The question whether there exists in the animal mechanism a capabil- 

 Formation of ity of forming fat from material in which it did not pre-exist 

 fat by bees. ma y -fo G considered as finally settled in the affirmative, after 

 much discussion, by the repetition of Gundelach's experiment by Dumas 

 and Milne Edwards. This experiment consisted in the feeding of bees 

 with honey nearly free from wax, and determining the quantity of fat in 

 their bodies at the beginning and end of the experiment, and also the 

 quantity of wax in the comb that they made. The following table gives 

 the result : 



Gramme. 



Fat found in the body of each bee at the beginning 0.0018 



Wax each bee consumed with the honey, not exceeding 0.0003 



Whole amount of fat derived from food 0.0022 



Wax secreted by each bee 0.0064 



Fat and wax in the body of each bee at end of experiment 0.0042 



From which it appears that a very large quantity of fat and wax had 

 been produced. 



Admitting thus that the animal system possesses the power of form- 

 The system * n & ^ at ^ * s P r bable that, under all circumstances, it carries 

 continually forward that function, though it may be at different rates on 

 generates fat. c | ifferent occas i ons< g uc h a production of fat probably com- 



