264: DIGESTION. 



ciple is its curious modifying influence upon Trommer's test 

 for sugar. Prof. Dalton first noted a peculiar interference 

 with this test in gastric juice taken from a fistula in a dog. 

 He found that a drop of honey mixed with a drachm or two 

 of gastric juice presented, on the addition of sulphate of cop- 

 per and a solution of potash, the following appearance: 

 On adding one or two drops of the solution of copper, the 

 ordinary faint blue tint was produced; "but on adding the 

 potash, instead of this producing a greater intensity in the 

 blue color, as is usually the case, the solution became of a 

 rich purple tinge, which changed to a yellow on boiling, 

 without any deposit of the suboxide of copper. This pecu- 

 liarity was found by Dalton to be due neither to the free 

 acid of the gastric juice nor to the organic matter ; for it was 

 present, both in gastric juice which had been neutralized, and 

 after the organic matter had been separated by boiling and 

 filtration. 1 A year later, the same fact was noted by Lon- 

 get, who ascertained that the peculiarity in the reaction was 

 due to the presence of albuminose, and assumed to be able 

 to distinguish in this way between albuminoid substances 

 and the principles resulting from their digestion in the stom- 

 ach ; ' an explanation which was afterward adopted by Dal- 

 ton. 3 In the experiments of Dalton, the secretion of gastric 

 juice was generally excited by feeding the animal with 

 small firm pieces of meat, the exterior having been hardened 

 by boiling water ; and obtained in this way, the filtered fluid 

 from the stomach, even that which flows immediately after 

 the introduction of the meat, generally contains a small 

 quantity of albuminose. 



Mialhe found, on evaporating albuminose to dryness, that 



1 DALTON, On the Gastric Juice and its Office in Digestion. American Jour- 

 nal of the Medical Sciences, October, 1854, p. 319. 



2 LONGET, Nouvelles Recherclies relatives d I 1 Action du Sue Gastrique sur lex 

 Matieres Albumino'idcs. Gazette Hebdomadaire, No. 6, Paris, fevrier, 1855, tome 

 ii., p. 103. 



3 DALTON, A Treatise on Human Physiologij, third edition, Philadelphia, 1864, 

 p. 143. 



