96 INFECTIONS OF THE DIGESTIVE TRACT 



the intestinal tract. In a dog that had hungered eleven 

 days, a period of three hours of exercise sufficed to per- 

 mit the free passage of microorganisms. It appears that 

 neither of these factors is capable of giving rise to this 

 degree of permeability when operating separately. Indi- 

 vidual peculiarities were, however, observed in respect 

 to the permeability of the tract, and these must have 

 their explanation in special conditions in the intestine. 



Ficker does not maintain that a full understanding 

 of the conditions favoring the permeability of the 

 intestinal tract has been reached through his experi- 

 ments. He holds very definitely that in fully grown 

 dogs, in which the intestinal tract is ordinarily little 

 permeable, it is possible through inanition or fatigue 

 or a combination of the two, to facilitate a penetration 

 of the intestinal mucous membrane which is analogous 

 to that observed in the infantile tract and further re- 

 sembles the conditions present in the dying organism. 

 Ficker suggests that under the influence of powerful 

 bodily action the volume of the gastric juice and of 

 other digestive juices is greatly reduced and that peri- 

 stalsis is diminished, while on the other hand the lymph 

 and blood flow are actively accelerated, all these being 

 factors which might favor the penetration of bacteria. 

 He suggests that perhaps the increased leucocytosis 

 induced by active muscular exertion is responsible for 

 the increased extravascular bactericidal power of the 

 serum which he observed, and thus that the leucocytes 

 can be regarded as carriers of bacteria from the intestinal 

 tract. Such a transportation of bacteria by leucocytes 



