BACTERIAL METABOLISM WITHIN THE BODY 691 



life. The former studies, which culminated in the comprehensive mono- 

 graph by Ford, showed quite clearly that the normal organisms were 

 quite closely related to the coli, proteus and mesentericus groups. This 

 is suggestive in that the normal bacilli of the alimentary canal which 

 exhibit chemical characteristics common to the colon-proteus-mesentericus 

 types remain dominant throughout adult life. 16 Observations by the au- 

 thor upon the residual intestinal flora of a man who starved for thirty-one 

 days supports this view. 



The other line of study considered more specifically the relations which 

 exist between the normal or abnormal chemical peculiarities of intestinal 

 processes of microbic causation, and the activities of specific bacteria. 

 The comprehensive monograph of Herter, summarizing his extensive con- 

 tributions to the field of excessive bacterial activity in the alimentary 

 canal, epitomizes the information upon this phase of the subject. Herter 

 also clearly recognized that the injection of lactic acid bacilli into the small 

 intestine of dogs reduced the excretion of ethereal sulphates in the urine, 

 while Bacillus coli and Bacillus proteus appeared to increase intestinal 

 putrefaction, thus foreshadowing the "lactic acid therapy" which Metch- 

 nikoff so forcefully presented in his work upon the prolongation of 

 life. About this time Sittler studied and summarized the corresponding 

 information with respect to the nursling. 



During this period of approximately twenty-five years there was an 

 ever-increasing precision of methods, both chemical and bacteriological, 

 and the last decade has witnessed the application of these procedures to 

 the study of bacterial metabolism under various conditions. As a result 

 of the application of these more refined methods to the study of bac- 

 teriological activities, a new viewpoint has presented itself. Many of 

 the conflicting statements and observations which had embarrassed earlier 

 investigators have been reconciled, and a fairly definite unification of 

 the phenomena underlying bacterial chemistry has led to renewed interest 

 in the highly important field of bacteriotherapy. 



Some of the more important relations of bacteriochemistry to bac- 

 terial metabolism in the alimentary canal follow. 



1. The Intestinal Bacteria of Normal Nurslings 



The Relation Between Diet and Microbic Response. The entire ali- 

 mentary canal of the newly born babe is sterile under normal conditions, 

 and the first bacteria appear in the intestinal tract several hours after birth 

 (Escherich). This earliest infection of the alimentary canal is by ad- 

 ventitious organisms derived from the environment of the infant. The 

 kinds of microbes found at this time are those which have gained en- 



16 This applies only to adults. The flora of nurslings is quite different and distinct 

 with reference to the type of bacteria and their characteristics. 



