USE OF SALIVA. 117 



goes on, whereas in ruminants it undoubtedly occurs in the 

 first two stomachs. Regarding the slight change observed 

 in food from its admixture with saliva in some animals, Dr 

 Dalton says: 



" If a dog, with a gastric fistula, be fed with a mixture of meat 

 and boiled starch, and portions of the fluid contents of the 

 stomach withdrawn afterward through the fistula, the starch is 

 easily recognisable by its reaction with iodine, for ten, fifteen, 

 or twenty minutes afterwards. In forty-five minutes, it is 

 diminished in quantity, and in one hour has usually alto- 

 gether disappeared ; but no sugar is to be detected at any 

 time. Sometimes the starch disappears more rapidly than 

 this; but at no time, according to our observations, is there 

 any indication of the presence of sugar in the gastric fluids. 

 Bidder and Smith have also concluded, from subsequent in- 

 vestigations, that the first experiments performed under their 

 direction by Jacubowitsch were erroneous; and it is now ac- 

 knowledged by them, as well as by the French observers, 

 that sugar cannot be detected in the stomach, after the in- 

 troduction of starch, in any form or by any method. In the 

 ordinary process of digestion, in fact, starchy matters do not 

 remain long enough in the mouth to be altered by the saliva, 

 but pass at once into the stomach. Here they meet with 

 the gastric fluids, which become mingled with them, and 

 prevent the change which would otherwise be effected by the 

 saliva. We have found that the gastric juice will interfere, in 

 this manner, with the action of the saliva in the test tube, as 

 well as in the stomach. If two mixtures be made, one of 

 starch and saliva, the other of starch, saliva, and gastric juice, 

 and both kept for fifteen minutes at the temperature of 

 1 00 P., in the first mixture the starch will be promptly con- 

 verted into sugar, while in the second no such change will 

 take place. The above action, therefore, of saliva on starch 



