74 Society for Experimental Biology and Medicine. 



the digesting mass ordinarily forms a firm pulp unlike the semi-fluid 

 contents of the human stomach. He therefore obtained the gastric 

 contents by causing dogs to vomit after injections of apomorphine. 

 Fifty trials made on 26 dogs after periods of 1,2, 3, 4, and 6 hours 

 with a single exception gave negative tests with Congo red paper, 

 Gunzburg's and Topfer's reagents, although the digesting masses 

 were always strongly acid to phenolphthalein. 



In several of the more recent investigations 1 on the gastric 

 digestion of dogs data are reported which indicate that fluid contents 

 with little or no free HC1 may be discharged through the pylorus. 

 I have therefore undertaken additional experiments with the co- 

 operation of Dr. Risley and Mr. Kleiner, to learn whether our 

 original observations on fistula dogs are in any way unique. The 

 dogs were given test meals of chopped meat (50-250 grams) with 

 or without water, and samples of the gastric contents were removed 

 at intervals through a stomach tube. By the simple device which 

 we use for suspending the animals (and which was demonstrated) 

 it is easy to obtain small portions for analysis. Frequently larger 

 fluid portions (1 5-60 c.c.) were easily removed. They were filtered 

 at once and tested qualitatively with Congo red paper, the trop- 

 aeolin 00 and dimethylaminoazobenzene reagents. Two c.c. were 

 titrated at o?ice with n/10 alkali, using Topfer's reagent and then 

 phenolphthalein as indicators for free HC1 and total acidity. 2 

 Twelve test meals fed to five different animals furnished measurable 

 quantities of free HC1 in ten cases. Even more positive results 

 might have been obtained if the removal of samples had been more 

 advantageously timed. The dogs had in no case been fed since 

 the preceding day. The accompanying summary of the essential 

 data tells its own story. 



The quantity of fluid gastric contents obtainable at any moment 

 is never large in the dog. Nevertheless our experience scarcely 

 justifies the assumption of a unique secretory regulation by which, 

 as Muller assumes, acid is furnisheds ufTRcient only to combine 

 with proteid material. For the cat also Cannon and Day 3 have 



1 Cf. e. g. Krehl : Pathologische Physiologic, 1904, 284; Lang: Biochemischc 

 Zeitschri/t, 1 906, ii, 240. 



2 Topfer's method as modified by Einhorn J New York Medical Journal, 1896, 

 xix, 603 ; cf. Chittenden, Mendel and Jackson : loc. cit., p. 191. 



3 Cannon and Day : American Journal of Physiology, 1903, ix, 402. 



