XXXIX. Gastric digestion, continued. 



j. Experiments and observations, continued. 



(9) To determine the influence of the hydrochloric acid of the 

 gastric juice upon putrefaction in the stomach. It has been 

 determined that the hydrochloric acid in the stomach 

 destroys, under favorable conditions, at least the non- 

 pathogenic forms of bacteria. Let us determine the 

 strength of acid necessary to destroy the common bac- 

 teria of putrefaction. To each tube used in experiment 

 (7) add a minute drop of any putrefying fluid. If the 

 contents of a tube serve as a good culture field any drop 

 of the fluid may be found to be swarming with bacteria 

 within a few hours. Within a few hours after infect- 

 ing the tubes examine under high power 700 to 1000 

 diameters a drop of the contents of each tube. 

 While making the observations take care not to 

 contaminate one tube with the contents of another. 

 That the tubes containing 5% or 2% or 1 % hydro- 

 chloric acid will be found to be free from bacteria goes 

 without saying. Just how weak may the acid be and 

 destroy the bacteria ? How weak may the acid be and 

 retard their development? Could one readily drink 

 enough liquid at a meal to change the stomach from a 

 sterilizing field to a culture field for the bacteria of 

 putrefaction ? 



(10) To determine the influence of neutral salts upon diges- 

 tion. Make a saturated aqueous solution of common 

 salt; also \ sat. sol, and fa sat. sol. 



( To 8 c.c. of NaCl sat. sol. add 1 c.c. of a 1% 

 177 



