THE EFFECT OF STASIS ON THE DEVELOPMENT OF 

 AMCEBIC DYSENTERY IN THE CAT 



By Andrew Watson Sellards 

 Of the Bureau of Science, Manila 



Lamberto Leiva 

 Of the College of Medicine and Surgery, University of the Philippines 



Extensive experimentation in the transmission of amoebic 

 dysentery to lower animals has served to emphasize three appa- 

 rently unrelated facts: (a) During the subpassage of virulent 

 strains of Entamoeba histolytica through a long series of kittens, 

 by rectal inoculation, a few individuals from time to time escape 

 infection; on reinoculation these animals are found to be just 

 as susceptible as are normal animals; (b) on the contrary, when 

 the caecum is exposed by laparotomy and the infective material 

 introduced directly through the wall of the caecum into the lumen 

 of the bowel, then infection takes place with surprising regular- 

 ity; (c) in either case, whether the amoebae are introduced into 

 the caecum or injected per rectum, the initial lesions occur in the 

 extreme lower portion of the large bowel. 



The occasional failure to infect a susceptible kitten with viru- 

 lent amoebae injected per rectum is not of itself remarkable, the 

 conditions naturally being somewhat uncertain as compared 

 with the injection of virulent protozoa and bacteria directly 

 into the tissues. The explanation for the constancy of infec- 

 tion after intracaecal inoculation is not immediately apparent. 

 Indeed, some authors, inexperienced in this mode of inoculation, 

 have denied the value of the procedure. The lesions develop, 

 not at the site of inoculation, but at the opposite end of the large 

 bowel. From the location of the early lesions it would be alto- 

 gether imposible to determine whether a kitten had been injected 

 per rectum or into the caecum. In any case, it seems a little 

 strange that the upper two-thirds of the large bowel, which is 

 practically a straight tube in the kitten, should escape damage 

 until after the process has secured a firm foothold in the lower- 

 most portion. It seemed to us not improbable that one single 



