SPEC/AL ARTICLES OF DIET. 
879 
of 500 grms. of meat. On removing 100 grms. of this from the diet, and 
replacing it by 200 grms. of gelatin, there was a gain of nitrogen to the 
body representing the putting on of 44 grms. of flesh, whereas when the 
100 grms. of meat was replaced by 200 grms. of fat, or by 250 grms. of 
starch, there was a loss of nitrogen representing a loss of flesh to the 
amount respectively of 50 and 39 grms. 
The following experiments of Yoit on a dog are also instructive. 
The numbers represent grammes : — 
Expt. 
Lean Meat. 
Gelatin. 
Flesh lost or gained. 
■1 
500 
500 

200 
-22 
-f 54 
*{ 
2000 
2000 

200 
+ 30 
+ 376 
•■! 
200 
200 
200 
300 
-118 
-82 
•{ 
200 
200 
+ 25 

200 
-118 
That it cannot wholly replace proteid is shown by the fact that 
even when very large quantities are given either alone or in combination 
with fat and carbohydrate, an excess of nitrogen appears in the excreta 
— in other words, there is still a loss of flesh from the body. 1 To a 
certain extent gelatin will act as a fat-sparer, i.e., when given along 
with proteid, it may prevent the oxidation of body fat, but its activity in 
this respect is far below that of either fats or carbohydrates. 2 Even 
the collagenous tissues can apparently not be formed from gelatin 
ingested, since this wholly appears (as urea, etc.) in the excreta ; these 
tissues must therefore be formed, like all others, from proteid food. 3 
Gelatin is also not assimilated if injected into the blood or under the 
skin : it appears at once in the urine. 4 
Nucleins and nucleo-proteids, as well as lecithins, are found in all 
forms of mixed diet ; and although nuclein is not digested by the gastric 
juice, nor, according to Bokay, 5 by artificial pancreatic juice, there are 
reasons for believing that a part at least of the nuclein of the food is 
absorbed and converted in the body into other substances. It is found, 
for example, that the ingestion of foodstuffs containing much nuclein 
causes a marked increase of uric acid in the urine, 6 and, as we shall 
show later on, there is strong reason to believe that the iron necessary 
for the formation of haemoglobin is derived from some forms of nuclein. 
1 For the evidence of this, see C. Yoit, op. cit.. S. 122. 
2 C. Yoit, op. cit., S. 126. 
3 An interesting historical account of the question of gelatin as an article of diet is 
given by Yoit {op. cit., S. 395). 
4 CI. Bernard and Barreswil, Jburn. de pharm. et ehim , Paris, 1844, Ser. 3, tome v. 
p. 425. 
5 Ztsckr. f. physiol. Chan., Strassburg, 1877, Bd. i. S. 157. 
6 Horbaczewski, Sitzungsb. d. k. AJcad. d. JFissensch.,~\Xieu, 1891, Bd. c. Abth. 3, S. 78. 
