AMOEBJ5 OF THE INTESTINAL TRACT. 165 



being found. When large quantities of the feces 

 were given to a cat it remained well and for four 

 weeks showed no amoebae in its feces. It was then 

 fed with the remnant of the dried feces used in the 

 first experiment, which contained multitudes of the 

 spores, and after six days the amoebae began to appear 

 in the feces. Being older and larger than the other 

 cat it proved more resistant to the infection and did 

 not die until two weeks later. The autopsy showed 

 the lesions of typical amoebic dysentery." 



These experiments of Schaudinn throw a flood 

 of light upon the interpretation of the negative re- 

 sults of some observers who have worked with Enta- 

 mceba Mstolytica. It will be remembered that during 

 the active stage of dysentery, when the symptoms are 

 acute, only the vegetative stages of this species occur 

 in the feces, and that these stages do not cause in- 

 fection, while the spores which are the infective agents 

 in this species only occur when the conditions for 

 vegetative existence are unfavorable, that is, when 

 the healing process has begun. If these points be 

 remembered the negative results obtained by feeding 

 or injection of feces from active cases of dysentery 

 can be explained, as in such cases the feces do not 

 contain the spores. If, however, the feces from cases 

 which are recovering be used for experimental pur- 



