42 The Philippine Journal of Science 



little more than half grown, only one became infected. This 

 illustrates the value of operative procedures for insuring amoe- 

 bic infection under special conditions. In our own work, in 

 localities where amoebic cases are common, we ordinarily inoc- 

 ulate several kittens per rectum under general anaesthesia, 

 passing a small soft catheter with as little disturbance as pos- 

 sible. However, if young kittens do not happen to be available, 

 or if working in a locality where amoebic dysentery is rare, we 

 always inoculate some animals intracaecally. By this procedure, 

 the amoebae are introduced into the bowel without breaking up 

 the formed faeces in the rectum, the general anaesthesia and the 

 laparotomy tending to produce constipation. 



We have endeavored to utilize some operative procedures in 

 experiments on monkeys. The frequency with which monkeys 

 are parasitized by entamoebas complicates the interpretation of 

 the results of inoculating them with Entamoeba histolytica. To 

 obviate some of the difficulty arising from spontaneous infec- 

 tion, the following experiment was carried out. A laparotomy 

 was done on a monkey (Pithecus philippinensis) under general 

 anaesthesia, and a ligature was passed around the tip of the 

 rather long caecum without interfering with the ileocaecal 

 valve. The needle of a syringe was passed through the tip of 

 the caecum, and the amoebae were inoculated directly into this 

 sac. It seemed not impossible that in healthy monkeys lesions 

 might be obtained in this sac and not in other parts of the 

 bowel. Thus far, some suggestive but no conclusive results 

 have been obtained. 



SUMMARY 



1. A laparotomy was performed on three cats under general 

 anaesthesia and a ligature placed around the large bowel in 

 order to produce stasis in its upper end. A suspension of 

 Entamoeba histohjtica was inoculated into the caecum. All three 

 animals developed lesions above the ligature. 



2. This experiment elucidates one factor in explaining (a) 

 the usual occurrence of the initial lesions of amoebic dysentery 

 in the cat in the lowermost portion of the large bowel; (b) the 

 superiority of intracaecal inoculations over injections per rectum 

 for insuring infection with amoebae; and (c) the occasional 

 failure of virulent amoebae to infect susceptible kittens. 



3. Stasis is probably an important factor in determining the 

 location of the lesions within the large bowel in spontaneous 

 amoebic dysentery in man. 



