296 "The Philippine Journal of Science mz 



Experiment XLIX. — Man 41, aged 50 years, had been under observation 

 in the prison three years and seven months. He had a negative dysenteric 

 history. No physical examination was made of his abdomen. He had not 

 been used for previous experiments. His stools v/eve negative, both cul- 

 turally and microscopically, for amoeboid organisms. He ingested cysts of 

 Enta7n(Bba histolytica, strain A, third passage, mixed with magnesium 

 oxide. Cultures of the stools of man 41 after the ingestion were negative 

 for amoebae. Microscopic examination of his stools showed Entmnceha 

 histolytica on the first day after feeding and thereafter. This man devel- 

 oped dysentery on the fifty-seventh day with abdominal pain and bloody 

 mucous stools containing motile Entamoeba histolytica. The dysentery lasted 

 two weeks. He was treated with ipecac, has recovered, and has had no 

 relapses. Entatnceha histolytica disappeared temporarily from this man's 

 stools following the ipecac treatment, but reappeared shortly and has 

 persisted ever since. 



Experiment L. — Man 42, aged 30 years, had been under observation in the 

 prison four years and eleven months. His history was negative for dysentery. 

 No physical examination was made of his abdomen. He had not been used 

 previously for experiments. Cultural and microscopic examinations of his 

 stools for amoeboid organisms were negative. He ingested encysted Enta- 

 moeba histolytica, strain A, third passage, mixed with magnesium oxide. 

 Cultures of the stools of man 42 after the ingestion were negative for amoebae. 

 Microscopic examination of his stools showed Entamoeba histolytica on the 

 fourth day and constantly thereafter. He has been under observation one 

 year since the experiment began. No dysenteric symptoms have appeared 

 up to the present time. 



Experiment LI. — Man 43, aged 38 years, had been under observation in 

 the prison three years and two months. His history was negative for 

 dysentery. No physical examination was made of his abdomen. He had 

 not previously been used for experiments. His stools were negative, cul- 

 turally and microscopically, for amoeboid organisms. This man ingested 

 encysted Entamoeba histolytica, strain A, third passage, mixed with mag- 

 nesium oxide. Cultures of the stools of man 43 after the ingestion were 

 negative for entamoebae. Microscopic examination of his stools have been 

 constantly negative for entamoeba, and he has been reserved as a non- 

 parasitized control. He has been under observation one year since the 

 experiment began. No dysentery has developed up to the present time. 



Experiment LII. — Man 44, aged 27 years, had been under observation in 

 the prison one year and three months. His history was negative for dys- 

 entery. No physical examination was made of his abdomen. He had not 

 been used for previous experiments. Cultures and microscopic examinations 

 of his stools for amoeboid organisms were negative. This man ingested 

 encysted Entamoeba histolytica, strain A, third passage, mixed with mag- 

 nesium oxide. Cultures of the stools of this man after the ingestion were 

 negative for amoebae. Microscopic examinations of his stools up to the 

 sixth day were negative for entamoebae. By an oversight his stools were 

 not examined again until the thirty-third day, when Entamoeba histolytica 

 was found, and has been found more or less constantly ever since, in his 

 stools. This man has been under observation one year since the experi- 

 ment began. He has shown no symptoms of dysentery up to the present 

 time. 



