632 PATHOGENIC MICROORGANISMS 



intermediation of leucocytic emigration during digestion. After 

 death, at autopsy, Bacillus coli is often found in the tissues and the blood 

 without there being visible lesions of the intestinal mucous membrane. 8 

 It is probable, also, that it may enter and live in the circulation a few 

 hours before death during the agonal stages. 



The distribution of the colon bacilli in the human intestine at dif- 

 ferent periods of life, and under varying dietetic conditions has been 

 considered in the section on the " normal flora of the intestinal canal," 

 p. 223. 



Extensive investigations have been carried out to determine whether 

 or not the constant presence of this microorganism in the intestinal 

 tract is an indication of its possessing a definite physiological function of 

 advantage to its host. It has been argued that it may aid in the fer- 

 mentation of carbohydrates. The question has been approached experi- 

 mentally by a number of investigators. Nuttall and Thierfelder 9 

 delivered guinea-pigs from the mother by Cesarean section and suc- 

 ceeded in preserving them from infection of the intestinal canal for 

 thirteen days. Although no microorganisms of any kind were found in 

 the feces of these animals, no harm seemed to accrue to them, and some 

 of them even gained in weight. Schottelius, 10 on the other hand, 

 obtained contradictory results with chicks. Allowing eggs to hatch 

 in an especially constructed glass compartment, he succeeded in 

 keeping the chicks and their entire environment sterile for seventeen 

 days. During this time they lost weight, did not thrive, and some 

 of them were moribund at the end of the second week, in marked 

 contrast to the healthy, well-nourished controls, fed in the same way, 

 but under ordinary environmental conditions. Although insuffi- 

 cient work has been done upon this important question, and no definite 

 statement can be made, it is more than likely that the function of the 

 Bacillus coli in the intestine is not inconsiderable if only because of its 

 possible antagonism to certain putrefactive bacteria, a fact which has 

 been demonstrated in interesting studies by Bienstock n and others. 12 



Pathogenicity. The pathogenicity of the colon bacillus for 

 animals is slight and varies greatly with different strains. Intraperi- 

 toneal injections of 1 c.c. or more of a broth culture will often cause 

 death in guinea-pigs. Intravenously administered to rabbits it may 



8 Birch-Hirschfeld, Ziegler 's Beitr., 24, 1898. 



9 Nuttall und Thierf 'elder, Zeit. f . Physiol. Chemie, xxi and xxii. 



10 Scltottelvus, Arch. f. Hyg., xxiv, 1889. 



11 Bienstock, Arch. f. Hyg., xxix, 1901. 



12 Tisser and Martelly, Ann. de Pinst. Pasteur, 1902. 



