DIGESTION IN THE SMALL INTESTINE. 413 



were collected in an hour, though, of course, the fluid was not derived 

 solely from the pancreas, but contained the secretion poured out by the 

 intestinal glands. 



The pancreatic secretion in the hog has certain characteristics which 

 are readily determined. The fistula is made in the same manner as in 

 the dog, and it is then seen that the hourly secretion is five to fifteen 

 grammes, and that the activity of the pancreatic secretion is in inverse 

 ratio to that of the bile. 



In the carnivora the study of this secretion is most readily carried 

 out. In the sheep it is open to difficulties, and has not been as 

 thorough as in the dog. No ratio between the size of the animal 

 or of the gland and the quantity of pancreatic juice is capable of 

 demonstration. Thus, the pancreas of the horse and ox weigh 

 each three hundred grammes ; both animals are about of the same 



FIG. 161. SECTION OF THE PANCREAS OF THE DOG IN THE FASTING CONDITION, 

 HARDENED WITH ALCOHOL AND STAINED \VITH CARMINE. (Heidenhain.) 



size, and also secrete the same amount of pancreatic juice. In the 

 sheep the pancreas weighs from fifty to sixty grammes, or one-fifth as 

 much as in the large ruminants, and yet only pours out seven to eight 

 grammes per hour. In the hog the pancreas weighs from one hundred 

 and forty to one hundred and eighty grammes, and only secretes ten to 

 fifteen grammes per hour. These results, of course, cannot be too posi- 

 tive^ accepted, on account of the many disturbing causes. 



In the pancreas, as in other glands, we may distinguish a period of 

 rest, during which the gland is pale and free from blood, and a period of 

 activity, during which it is swollen and its vessels gorged with arterial 

 blood. Changes occur, therefore, in the pancreas such as have been al- 

 ready described in the case of the salivary glands. In the carnivorous 

 animals the secretion commences when the food is introduced into the 



