136 THE BODY AT WORK 



were present in their alimentary tracts. Yet in all animals 

 under ordinary conditions bacteria are present in great numbers, 

 at any rate, after the nursing period, and, for good or ill, 

 produce important fermentations. Only a single bacillus 

 (B. -bifidus), and that a friendly germ, is, it is asserted, present 

 in the intestines of an infant at the breast ; whereas a bottle- 

 fed baby houses a variety of parasites. 



In the stomach, sugars are changed by the Bacterium acidi 

 lactici into lactic acid, which is further split into butyric acid, 

 carbonic acid gas, and hydrogen. Succinic acid and other sub- 

 stances are also formed. This occurs in the first stage of gastric 

 digestion. When a considerable quantity of hydrochloric acid 

 has been poured out, lactic fermentation is stopped. The small 

 amount of gaseous products formed normally is of little con- 

 sequence ; but flatulence is a most annoying symptom of in- 

 digestion. " Put your trust in Providence, and you will feel 

 more cheerful after luncheon," Dr. Jowett is alleged to have re- 

 marked to a despondent friend. The presence of food stimulates 

 the stomach to contraction. Accumulated gases are expelled. 

 Hydrochloric acid is secreted, and puts a stop to fermentation 

 for a time. But if the meal be too heavy or the mucous mem- 

 brane in an irritable condition, the contents of the stomach 

 become unduly acid in the later stages of digestion. Other 

 bacteria then develop, leading to fresh trouble ; more gases 

 accumulate, and the dyspeptic's distress is greater than it was 

 before. Unfortunately, antiseptics, such as creosote, and car- 

 minatives, such as oil of lavender, oil of peppermint, or alcohol, 

 which for the moment give relief, increase irritability, and 

 consequently in the long-run make matters worse. It is the 

 fermentation of the later stages of digestion which causes most 

 annoyance. Admirable as was the Master of Balliol's advice, 

 it hardly took account of the fact that bacteria which cause 

 flatulence, with its resultant feeling of oppression, are derived 

 for the most part from the imperfectly digested, and therefore 

 actively fermenting, remnants of food which were present in 

 the stomach when the meal was taken. It would be far 

 beyond the scope of this book to consider the pathology of 

 dyspepsia ; but the study of normal conditions reveals the 

 fact that some amount of fermentation invariably occurs. 

 The Bacterium acidi lactici is always present in the stomach. 



