FUNCTIONS OF THE SALIVA. 177 



among which may be mentioned the serum of the blood, the 

 fluid found in cysts, and mucus, have the same property ; 

 although none, except the intestinal juices, are nearly so effi- 

 cient as the saliva. And again, the quantity of starch contained 

 in the food is so great that it would require, apparently, a 

 longer contact with the saliva than usually takes place in the 

 mouth to make this action very effective. These considera- 

 tions make it necessary to follow the amylaceous principles 

 of food into the stomach, and ascertain, if possible, whether 

 the transformation into sugar be continued in this organ. 



Bernard, after feeding a dog with starch, drew off the 

 contents of the stomach by a gastric fistula, and found the 

 starch unchanged, with no traces of sugar. 1 This experi- 

 ment we have often repeated in public demonstrations, with 

 the same results ; but the differences already noted in the 

 properties of the saliva of the human subject and of the in- 

 ferior animals destroy much of the value of this observation. 

 Longet 2 and others have show r n that the addition of gastric 

 juice to the saliva does not interfere with the action of the 

 latter on starch, but it has been found that the reaction of 

 the sugar thus resulting from the transformation of the starch 

 is masked by the presence of other principles contained in the 

 stomach. The question of the continuance, in the stomach, 

 of the digestion of starch by the saliva is settled by the fol- 

 lowing observation by Griinewaldt and Schroeder, in 1853, 

 on a woman with a gastric fistula : 3 



" After a meal of raw starch, no sugar was found in the 

 contents of the stomach, the acid juice was drawn by the 

 fistula, and was mixed with paste ; the transformation into 

 sugar commenced immediately. As Bidder has observed, 

 the transforming property of the saliva persists, even in the 

 presence of free acids. 



" A few ounces of starch swelled with boiling water were 



: Op. cit., p. 159. 



2 LONGET, Traite de Physiologic, Paris, 1861, tome i., p. 173. 

 8 Cited by LONGET, op. cit., p. 174. 

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