34 THE WORK OF THE DIGESTIVE GLANDS. 



The dog received 200 c.c. of milk. 



Time. Quantity of juice in c.c< Digestive power in nun. 



8:30-1). 30 A.M. , ; ; 7'0 ... 1-5 



10.80 ,;.... li'O 2-0 



145 grms, of bread were now given. 



11.30 A.M. .... 2-0 3'37 



12.30 P.M 3'6 ... 5-0 



200 c.c. of milk again given. 



1.30 P.M 5-4 ... 3-37 



2.30 3-4 2-0 



Not alone the digestive power, but likewise the total acidity,* varied 

 according to the nature of the diet. The latter is, however, greatest 

 with flesh (0-56 per cent.) and lowest with bread (0 - 4T> per cent.). 

 In a similar way the quantity of juice poured out and the dura- 

 tion of its secretion are dependent upon the kind of food. And this 

 relationship is equally clear whether, when estimating the food, one 

 takes into consideration its total quantity, or its amount of dried sub- 

 stance, or, lastly, its content of nitrogen (since the gastric juice acts only 

 on its proteid constituents). 



If the quantity of juice produced during a given digestion period be 

 divided by the number of hours in the period, the mean hourly quantity 

 of juice is obtained. Even this number, which represents the mean 

 hourly intensity of gland work, is different for the different sorts of 

 food. Comparing equivalent weights, flesh requires the most, and 

 milk the least gastric juice ; but taking equivalents of nitrogen, bread 

 needs the most and flesh the least. The hourly intensity of gland work 

 is almost equal in the case of milk and flesh diets, but far less, with 

 bread. The last, however, exceeds all the others in the time required 

 for its digestion, and the duration of the secretion is correspondingly 

 protracted. 



Nor is this speciality of gland work, which depends on the variety of 

 the food, limited to the distinctions given. It likewise prominently 

 reveals itself in the hourly rate of secretion and in the qualitative 

 variations of the juice. This time I furnish only one example for 

 each kind of food, and beg you to believe that it repeats itself with the 

 same admirable precision which we have already seen. 



* The acid was estimated titrimetrically, and is expressed in percentages 

 of HC1. 



