ARE FATS FORMED FROM PROTEIDS OF FOOD 1 933 
fatty serie8 are formed. And although it is not easy at first sight to 
understand, from a chemical point of view, how carbohydrate molecules are 
transformed into fatty molecules, we are not obliged to assume direct trans- 
formation, for it may well he that the carbohydrates are broken down into 
comparatively simple compounds, and that these are built up again by the 
organism into fat. 
The observations of Hanriot, with Richet, 1 furnish indirect evidence of the 
transformation of carbohydrate into fat. These observers found that, with the 
administration of carbohydrate food, there is a greatly increased output of 
carbon dioxide without a corresponding increase of oxygen intake. This fact 
may be explained, according to Hanriot, by a transformation of carbohydrate 
into fat,- in conformity with such an equation as the following : — 
13(C 6 H 12 6 ) = C 55 H 104 O 6 + 23(CO,) + 26(H 2 0) 
(oleo-stearo- 
palmitin) 
Are fats formed from the proteids of the food ? — This is a question 
which was for many years held to have been settled by the experiments 
of Pettenkofer and Voit, and subsequently of Voit. 3 These observers 
found that if a dog is kept in a respiration chamber, and fed entirely on 
lean meat, all the ingesta and egesta of the body being carefully deter- 
mined and analysed, a comparison of the results shows clearly that in 
many cases carbon of the proteid is retained within the body, and is 
presumably in the form of fat, the amount of fat and carbohydrate in 
the food being altogether too small to suppose that the carbon laid by 
could have been derived from anything but the proteids of the food. 
Moreover, proteid food increases the amount of fat in the milk of 
suckling animals, and a bitch fed upon lean meat may produce much 
more fat in her milk than can be accounted for by the fat and carbo- 
hydrates of the food — produces, indeed, milk especially rich in fat, when 
fed exclusively on lean meat. 4 
In confirmation of observations of this kind have been adduced the 
statements that the milk of suckling animals and of nursing women 
is richer in cream in proportion to the amount of proteid taken in the 
diet; that fat becomes formed in large amount by the larvae of blow- 
flies, which are fed upon defibrinated blood, containing only very small 
quantities of non-proteid organic material; 5 that in the ripening of 
cheese there is a diminishing amount of proteid, and an increasing 
amount of fat ; 6 and that in the formation of adipocere from flesh, there 
is found a diminished amount of proteids, and an increased amount of 
fatty acids. 7 The formation of fat in the liver and tissues of a starving 
1 CoiDjif. rerid. Acad. d. sc, Paris, 1892, tome cxiv. p. 371. 
2 Cf. also Gautier, ibid. , p. 374. 
3 Ann. d. Chem. u. Pharm., 1862, Suppl. Bd. S. 52 and 361; Ztschr. f. Biol., 
Miinchen, 1869, Bd. v. ; also 1870 and 1871, Bde. vi. and vii. ; art. " Ernahrung, " in 
Hermann's "Handbuch," Bd. vi. S. 249. 
4 Ssubotin, Virchow's Archiv, 1886, Bd. xxxv. S. 561; and Centralbl. f. d. vied. Wiss- 
ensch., Berlin, 1866, S. 337 ; Kemmerich, ibid., S. 467. Both Ssubotin and Kemnierich 
worked with Pfliiger. See also Voit, Ztschr. f. Biol., Miinchen, 1869, Bd. v. S. 137. 
5 Fr. Hofmann, Ztschr. f. Biol., Miinchen, 1872, Bd. viii. S. 159. 
6 See on the changes accompanying the ripening of cheese, Sieber, Journ. f. prdkt. 
Chem., Leipzig, 1880. N. F., Bd. xxi. S. 203: Jacobsthal, Arch. f. d. ges. Physiol., Bonn, 
1S93, Bd. liv. S. 484. 
7 Lehmann {Sitzuwjsb. d. phys.-med. Gesellsch. zu Wilrzburg, 1885, S. 19) obtained an 
increase of fatty acids to the extent of 3 "7 per cent, in meat kept in running water for some 
months. E. Voit [Miinchen. vied. JFchnschr., 1888, S. 518) got an increase of 2 per cent, 
when it was kept in milk of lime, thus excluding fungi. 
