716 BACTERIA IN AIR, SOIL, WATER, AND MILK 



remains, however, that, whatever may be the specific cause, the disease 

 itself, a grave and often fatal affliction, may be clinically traced, in a 

 number of cases, to the absorption of poisons from the intestinal canal, 

 and it is more than likely that these poisons are the products of bacterial 

 activity. Reason dictates, furthermore, that the bacteria primarily 

 responsible for the production of these toxic substances do not belong to 

 the varieties which attack carbohydrates only, but must belong to that 

 class of aerobic and anaerobic germs which possess the power of breaking 

 up proteids in other words, the bacteria of putrefaction. 



On the basis of the mutual antagonism existing in culture between 

 many acid-producing bacteria and those of putrefaction a phenomenon 

 recognized by some of the earliest workers in this field, many investiga- 

 tors have suggested the possibility of combating intestinal putrefaction 

 by adding acid-forming bacteria together with carbohydrates to the diet 

 of patients suffering from this condition. The first to suggest this 

 therapy was Escherich * who proposed the use, in this way, of Bacillus 

 lactos aerogenes; with the same end in view, Quincke, 2 a little later, 

 suggested the use of yeasts Oidium lactis. The reasoning underlying 

 these attempts was meanwhile upheld by experiments carried out both 

 in vitro and upon the living patient. Thus Brudzinski 3 was able to 

 demonstrate that Bacillus lactis aerogenes, in culture, inhibited the 

 development of certain races of the proteus species and succeeded in 

 obtaining markedly favorable results by feeding pure cultures of Bacillus 

 lactis aerogenes to infants suffering from fetid diarrhea. Similar ex- 

 periments 4 carried out with the Welch bacillus (aerogenes capsulatus) 

 and Bacillus coli, however, had no such corroboratory results, since this 

 anaerobe possesses a considerable resistance against an acid reaction. 

 In considering the difficulties of the problems involved in this question, 

 it occurred to Metchnikoff 5 that much of the practical failure of therapy, 

 based upon the principles stated above, might be referred to insufficient 

 powers of acid production on the part of Bacillus coli, Bacillus lactis 

 aerogenes, and other germs previously used. In searching for more pow- 

 erful acid producers, his attention was attracted to Bacillus bulgaricus, 



1 Escherich, Therapeut. Monatshefte., Oct., 1887. 



2 Quincke, Verhandl. des Congress f . Inn. Med., Wiesbaden, 1898. 



3 Brudzinski, Jahrbuch f. Kinderheilkunde, 52, 1900 (Erganzungsheft). 



4 Tissier and Martelly, Ann. de 1'inst. Pasteur, 1906. 



5 Metchnikoff, "Prolongation of Life," G. P. Putnam's Sons, N. Y.; also in "Bac- 

 te"riotherapie," etc. " Bibliotheque de the"rapeutique," Gilbert and Carnot, Paris, 

 1909. 



