SUGAR. 283 



even normal mucus, may not possess this property, or, at all 

 events, may not attain it at the temperature of the animal body, 

 this, at all events, is certain, that all these materials collectively do 

 not so rapidly excite the lactic acid fermentation as the special 

 intestinal juice. 



I agree with Frerichs and Schmidt that the pure acid gastric 

 juice of dogs, in the state in which we obtain it from gastric fistulee, 

 does not convert sugar into lactic acid even after several hours' 

 digestion ; but if the gastric juice be mixed with much saliva, or 

 if we add to it a small piece of the glandular coat of the stomach 

 of the pig, lactic acid may certainly be detected in the mixture 

 after 3 or 4 hours. Hence we believe that, at all events at the 

 present time, the possibility of a formation of lactic acid in the 

 stomach cannot be altogether denied, although it is not at all 

 probable that, under ordinary conditions, any appreciable quantity 

 of starch or sugar undergoes this change. 



If we allow saliva to remain in contact with sugar of milk, or 

 even with starch, at a temperature of from 30 to 40, a little 

 free acid is certainly formed, but so long a time (often from 16 to 

 32 hours) is required for its development,' as almost to exclude the 

 idea that the saliva in any degree contributes to the conversion of 

 the sugar into lactic acid. 



Heintz and van den Broek* support the view that the bile 

 contributes in a special manner to the conversion of the sugar 

 into lactic acid, and the well-known observation, that we generally 

 find the contents of the duodenum more intensely acid than those 

 either of the stomach or of the jejunum, favours this view ; but, 

 notwithstanding this, I cannot unconditionally adopt this opinion, 

 for altogether independently of the circumstance that, as has been 

 already mentioned, the intestinal juice alone, without the bile, can 

 induce the lactic acid fermentation, and that the intensely acid 

 reaction of the duodenal contents admits very readily of another 

 solution, the action of the bile on sugar is of so slow and gradual 

 a nature, that we cannot regard this function even as a secondary 

 object of the flow of bile into the intestinal canal. Every one 

 who has repeated Meckel's experiment of allowing bile to ferment 

 with sugar, in the same manner that Schiel has done (see vol. i, 

 p. 25 7? and vol. ii, p. 104), must have convinced himself that it 

 is only very slowly that the acidity is developed in the bile ; and 

 this is especially the case when we employ for the experiment bile 

 that has been filtered, or that has been removed with extreme care 

 * Zeitschr. f. rat. Med. Bd. 8, S. 343. 



