VARIATIONS DEPENDENT UPON DIET. 37 



on bread, 1(!00 ferment units; on flesh, 430; and on milk, 340. These 

 figures I have obtained MS follows: 100 grms. of flesh contain ap- 

 proximately the same amount of nitrogen as (500 c.c. of milk and 250 

 grms. of white bread. As shown by Dr. Chigin on 



100 grms. flesh, 27 c.c. of juice of 4'0 nun. digestive strength, 



and on 



GOO c.c. milk, 34 c.c. juice of 3'1 mm. digestive strength 



are secreted. For 250 grms. bread we find no corresponding data, 

 since he experimented with different quantities. They may, however, 

 be easily constructed from the data at hand, on the basis of a proportion 

 between amount of food ingested and the quantity of juice secreted. 

 It results that for 



250 grms. white bread. 42 c.c. of juice of 6'1G mm. strength 



are secreted. 



The squares of the digestive strengths (in millimetres) yield 38 for 

 bread, 1(! for flesh, and 10 for milk. These figures afford us the 

 possibility of comparing the ferment concentrations in similar volumes 

 of juice. Since, however, different quantities of juice are called forth 

 by the different varieties of food, we must take this also into considera- 

 tion in calculating the quantities of ferment. Multiplying, therefore, 

 the squares of the numbers representing digestive strengths by the 

 number of c.c. poured out on the corresponding food, we obtain the 

 above-mentioned numbers, 1000, 430, and 340. These indicate that, on 

 proteid in the form of bread, five times more pepsin is poured out than 

 on the same quantity of proteid in the form of milk, and that flesh 

 nitrogen requires 25 per cent, more pepsin than that of milk. These 

 different kinds of proteid receive, therefore, quantities of ferment corre- 

 sponding to the differences in their digestibility which we already know 

 from physiological chemical experiments. 



When comparing the work of the gastric glands with different 

 foodstuffs, we must recognise that it is purposive in another sense also. 

 The vegetable proteid of bread requires for its digestion much ferment. 

 This demand is supplied less by an increase in the volume of the juice 

 than by an extraordinary concentration of the fluid poured out. One 

 may conclude from this that it is only the ferment of the gastric juice 

 which is here in great requisition, whereas considerable quantities of 

 hydrochloric acid would remain unused, possibly, indeed, would be 

 injurious. We see, from other properties of the juice in this case, 

 that as a matter of fact during the digestion of bread by the stomach 

 an excess of hydrochloric acid is avoided. The total quantity of juice 

 secreted on bread is only a little larger than that secreted on milk. It 



