DIGESTION 329 



the intestine from the bacteria-infested regions of the mouth 

 and pharynx, and to destroy or inhibit the micro-organisms 

 swallowed with the food and saliva. The occasional presence 

 in vomited matter of sarcinae or regularly arranged groups of 

 micrococci, generally four to a group, shows that under abnormal 

 conditions the gastric contents are not perfectly aseptic ; and 

 even from a normal stomach active micro-organisms of various 

 kinds can be obtained. But upon the whole there is no doubt 

 that the acidity of the gastric juice is an 'important check on 

 bacterial activity during the first part of digestion, and in the 

 upper portion of the alimentary canal. Koch has shown that 

 the acidity of the gastric juice of a guinea-pig is sufficient to 

 kill the comma bacillus of cholera. Normal guinea-pigs fed 

 with cholera bacilli were unaffected. But if the gastric juice 

 was neutralized by an alkali before the administration of the 

 bacilli the guinea-pigs died. Charrin found, too, that digestion 

 with pepsin and hydrochloric acid causes an appreciable destruc- 

 tion or attenuation of diphtheria toxin. Bacteria, like the 

 lactic acid bacillus, which form acid products, may be less pro- 

 foundly affected by the acid gastric juice than the putrefactive 

 bacteria, which, on the whole, form alkalies, and are therefore 

 accustomed to an alkaline medium. Yet we have seen that the 

 growth of even the lactic acid bacillus is very strictly controlled 

 when the gastric juice contains the normal amount of hydro- 

 chloric acid. 



It has been supposed by some that this bactericidal action 

 is the chief function of the stomach, and the question has been 

 asked why we should attribute any digestive importance to the 

 secretion of that viscus, since the pancreatic juice can do all 

 that the gastric juice does, and some things which it cannot 

 do. Further, it has been shown that a dog may live five years 

 after complete excision of the stomach, comport himself in all 

 respects like a normal dog, and when killed for autopsy show 

 every organ in perfect health (Czerny). In man, too, the stomach 

 has been excised with a successful result. But if this is to be 

 admitted as evidence against the digestive function of the 

 stomach, it is just as good evidence against the bactericidal 

 function, particularly as it has in addition been shown that 

 even putrid flesh has no harmful effect on a dog after excision 

 of the stomach, any more than on a normal dog. And, indeed, 

 the reasoning is fallacious which assumes that what may happen 

 under abnormal conditions must happen when the conditions 

 are normal. For nothing is impressed more often on the physio- 

 logical observer than the extraordinary power of adaptation, of 

 making the best of everything, which the animal organism 



