40 The Philippine Journal of Science m* 



factor might have an important bearing on these three features. 

 Certainly, the short and straight large intestine of the kitten 

 presents no striking differences along its course. However, the 

 contents of the proximal two-thirds are fluid, while in the lower 

 third there occur formed faeces with moderate secretion of 

 mucus. The question of how Entamoeba histolytica can injure 

 and penetrate the normal mucosa has been much discussed, but 

 this point of stasis in the distal end of the bowel certainly 

 affords an opportunity for the organisms to gain a foothold. 

 The subsequent dissemination of the lesions indicates that there 

 are no pronounced differences physiologically in the suscepti- 

 bility of various areas of the large bowel. 



The importance of stasis as a factor in determining the loca- 

 tion of the initial lesions was tested experimentally. The large 

 intestine of a half -grown cat was exposed by laparotomy under 

 general anaesthesia. A broad ligature was placed around the 

 middle of the bowel and tied tightly enough to obstruct the 

 lumen. A suspension of Entamoeba histolytica, obtained by 

 sacrificing an infected cat, was injected into the caecum. There 

 was no indication of any postoperative discomfort. Two days 

 later, the animal was sacrificed. Below the ligature the large 

 intestine was practically free of faecal matter and showed no 

 lesions. Above the ligature, in the caecum, 3 centimeters from 

 the point of inoculation, one well-developed lesion was present 

 which contained numerous individuals of E. histolytica. 



In a second experiment, two adult animals were operated 

 upon in the same way, the ligature being placed at the junction 

 of the upper and the middle thirds of the large bowel. The 

 inoculation of amoebae was made through the tip of the caecum. 

 At the same time, ten other animals that were to be used for 

 other work were inoculated per rectum under general anaesthesia. 

 These ten were injected with amoebae before the inoculations were 

 performed on the two that required operation. The time that 

 elapsed between the sacrificing of the infected kitten for the 

 amoebic material and the completion of the inoculations was one 

 hour and twenty minutes. Of the animals receiving rectal 

 injections, two kittens and one half -grown cat became infected; 

 the other seven remained negative. The two adults, inoculated 

 intracaecally, were sacrificed on the third day. Both showed 

 extensive lesions. In one, the bowel below the ligature con- 

 tained only clear viscid fluid in which a few individuals of 

 Entamoeba histolytica were seen. There was no trace of macro- 

 scopic lesions. Immediately above the ligature, there was 



