280 The Philippine Journal of Science 1913 



examinations, both before and after a purgative, were made of 

 their stools, and all men showing amoeboid organisms after either 

 method of examination were excluded. 



Five distinct strains of Entamceba coli were employed as 

 follows : 



Strain A, from a healthy Filipino. 



Strain B, from a Filipino suffering from an epithelioma of the jaw. 



Strain C, from a healthy Filipino. 



Strain D, from a Filipina, suffering from lobar pneumonia. 



Strain E, from a healthy American. 



Entamoeba coli was fed for the most part in the encysted stage, 

 since there are reasons for believing it to be the stage naturally 

 infective and it was the purpose of these experiments to secure 

 as high a percentage of parasitization as possible in order to 

 determine the pathogenesis of this species. 



The entamcebse were mixed with powdered starch or magne- 

 sium oxide, inclosed in gelatine capsules, and ingested by the 

 men. The starch or magnesium oxide was used, as in the ex- 

 periments with the cultures of amoeba, to absorb the excess of 

 moisture that might dissolve the gelatine capsule and to facili- 

 tate the ingestion of the material. The magnesium oxide, when 

 used, served also to neutralize the acidity of the contents of the 

 stomach of the man. It is doubtful if this be necessary to 

 secure parasitization with the entamcebse, since the action of 

 the gastric juices probably plays an important part in the dis- 

 solution of the cyst wall of the parasite. However, it was em- 

 ployed in certain of these experiments to correspond with the 

 feeding experiments with the cultures of amoebse. The percent- 

 age of parasitizations with Entamoeba coli did not appear to be 

 materially affected by its use. 



Following the ingestion of material containing Entamceba coli, 

 the stools of the men were examined daily, culturally and micro- 

 scopically, for amoeboid organism until it was determined that 

 the ingested entamoebee had parasitized or failed to parasitize 

 the man, and thereafter at frequent intervals. The men were 

 examined clinically and physically whenever conditions seemed 

 to warrant. 



A complete protocol is given of each man in order to put on 

 record the details of these experiments. 



Experiment XXL— Man 11, aged 26 years, had been under observation 

 in the prison for six years and two months. He had not been used for 

 previous experiments. He gave a history of one attack of dysentery 

 eight years ago. Physical examination of his abdomen and microscopic 

 and cultural examinations of his stools for amoeboid organisms were 



