372 PHYSIOLOGY OF THE DOMESTIC ANIMALS 



feeding with hay. Of course, this does not represent the total amount 

 formed, as a great deal will have been absorbed, some converted into 

 lactic acid, and some will have passed into the small intestine. 



Ellenberger, Hofmeister, and Goldschmidt found that the naturally 

 mixed saliva of the horse possessed a strouger amylolytic action than 

 the artificially combined separate salivary secretions ; and that each 

 separate salivary secretion, though highly amylolytic, was less so than 

 the mixed secretions; and, finally, that the conversion in the horse's 

 stomach of starch into dextrin, sugar, and lactic acid occurred to a 

 greater degree than could be attributable to the fermentative action of 

 the saliva alone. The conclusion is, therefore, drawn that in the horse's 

 stomach amylolytic digestion is aided by ferments developed in the 

 alimentary canal and in the food itself. This latter statement is con- 

 firmed by the fact, already mentioned, that Hofmeister has found in oats 

 an amylolytic ferment, which is destroyed at the temperature of boiling 

 water, but which is active at the body temperature, thus explaining the 

 fact that more starch is converted into sugar in the stomach than is 

 attributable to the action of the salivary ferment alone. Finally, 

 Goldschmidt has found that the digestion of starch in the horse is 

 aided by amylolytic ferments derived from the air, which are mixed 

 with the saliva in the mouth, and which rapidly develop in the oral 

 mucus 



In the horse's stomach vegetable albumen is rapidly digested and 

 turned into peptone, which increases in amount with the duration of 

 digestion. After a large meal the peptonization is at first slight, since 

 the glands cannot form acid and pepsin fast enough to digest a large 

 meal rapidly. If, then, another meal is taken before the first is digested, 

 the former food is forced in an undigested state into the intestine. 

 After a moderate meal the digestion reaches its maximum in three to 

 four hours ; in other words, digestion is then complete. The larger 

 quantity of peptone is found in the stomach after oats have been given 

 than after. feeding with hay. Five to forty grammes of peptones have 

 been found : after oats have been given, while only about six grammes 

 were found six hours after feeding with hay. Of course, these figures 

 do not indicate the total amount of peptones formed, since, probably, a 

 large portion would be absor-bed almost as mpidiy as formed. As hay 

 absorbs four times its weight of saliva, it is readily digested at first 

 without water, but the digestion then becomes slow. Colin administered 

 twenty-five hundred grammes of hay to a horse, and then killed him. 

 Only seven thousand grammes of material were found in the stomach, 

 representing, therefore, but little more than one-half the amount given, 

 since the two thousand five hundred grammes of hay would have absorbed 

 ten kilos of saliva. Of this residue only one thousand grammes were dry 



