406 PHYSIOLOGY OF THE DOMESTIC ANIMALS. 



(a) Action on Carbohydrates. — Valentin pointed out that the 

 pancreatic juice was capable of converting starch into sugar, and nearly 

 all that was stated with regard to the action of saliva on starch might be 

 repeated for the case of the pancreatic juice, with the single modification 

 that in the case of the pancreas the amylolytic power possessed by its 

 secretion is much stronger than that of the saliva. The secretion and 

 watery extract of this gland in both herbivora and carnivora, as well as 

 the secretion obtained from this gland in birds (chicken and goose), 

 rapidly convert starch into sugar. All the conditions which were found 

 to prevent the action of the saliva also hold here, with the single excep- 

 tion that a slight degree of acidity seems rather to favor the action. The 

 ferment through whose action the pancreatic juice is enabled to convert 

 starch into sugar is apparently formed in the gland-tissue by the trans- 

 formation of some previously existing material; since it has been found 

 that if the ferment is completely extracted from a fresh gland by glyc- 

 erin, and the inactive residue allowed to remain on the filter for five or 

 six hours exposed to the air, a further production of ferment occurs. 

 This new formation may be again extracted by water or glycerin. That 

 this result is really due to the new formation of ferment, and not to the 

 occurrence of decomposition, is proved by the fact that if the watery ex- 

 tract of the pancreas is once deprived of its action on starch by boiling, 

 this power never returns in any stage of the subsequent decomposition. 

 So, also, a gland which has been exposed for twenty-four hours to the 

 air is more active than a fresh gland. The amount of starch which by 

 the action of pancreatic diastase is converted into sugar is almost infinite. 

 Roberts has calculated that pancreatic diastase is able to transform into 

 sugar and dextrin no less than forty thousand times its own weight of 

 starch. The rapidity with which starch is converted into sugar depends 

 upon the proportion of ferment brought to act upon it. So that all 

 grades of activity may exist between the apparently instantaneous con- 

 version of a small amount of starch with a large amount of ferment, and 

 the slow and gradual action of a small amount of ferment on a large 

 quantity of starch. The products which result from the action of pan- 

 creatic ferment on starch are entirely analogous to those which result 

 from the action of ptyalin or malt-diastase on starch. When the gland- 

 tissue is itself brought into contact with soluble carbohydrates, lactic 

 acid fermentation ultimately results. Glycogen is also rapidly converted 

 into sugar under the action of pancreatic diastase. Inulin and cane-sugar 

 are entirely unaltered by it. The amylolytic action of the pancreatic 

 juice is said to be absent in newborn children, appearing first after the 

 termination of the second month. 



(&) Action on Fats.— In the small intestine the fats, which have been 

 seen to almost entirely escape the action of the gastric juice, are broken 



