VIII, B, 4 Walker and Sellards: Entamcebic Dysentery 283 



experiments. His history with reference to dysentery was negative. No 

 physical examination of his abdomen was made. Cultural and microscopic 

 examinations of his stools for amoeboid organisms were negative. He 

 ingested cysts of Entamoeba coll, strain C, mixed with magnesium oxide. 

 This man was under observation four months after this experiment began. 

 Cultures of his stools for amoebae were constantly negative. Microscopic 

 examination showed Entamoeba coli in his stools on the second day and 

 more or less constantly thereafter. No symptoms of dysentery developed. 



Experiment XXXI. — Man 19, aged 30 years, had been under observation 

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

 experiments. His history with reference to dysentery was negative. No 

 physical examination of his abdomen was made. Cultural and micro- 

 scopic examinations of his stools for amoeboid organisms were negative. 

 He ingested cysts of Entamoeba coli, strain C, mixed with magnesium oxide. 

 This man has been under observation one year and six months since this ex- 

 periment began. Cultures of his stools for amoebae have been constantly 

 negative. Microscopic examination of his stools for entamcebse have also 

 been negative; that is, this man failed to become parasitized with Enta- 

 moeba coli. No symptoms of dysentery have developed. 



Experiment XXXII. — Man 20, aged 47 years, had been under observa- 

 tion in the prison for four years and one month. He had not been used 

 previously for experiments. He had a negative dysentery history. No 

 physical examination of his abdomen was made. Cultural and microscopic 

 examinations of his stools for amoeboid organisms were negative. He 

 ingested cysts of Entamoeba coli, strain D, mixed with magnesium oxide. 

 This man has been under observation one year and three months since this 

 experiment began. Cultures of his stools for amoebae were constantly nega- 

 tive. Microscopic examination showed Entamoeba coli in his stools on the 

 sixth day and thereafter. No symptoms of dysentery have developed. 



Experiment XXXIII. — Man 21, aged 30 years, had been under observa- 

 tion in the prison five years and one month. He had not been used 

 previously for experiments. His history with reference to dysentery was 

 negative. No physical examination was made of his abdomen. Cultural 

 and microscopic examinations of his stools for amoeboid organisms were 

 negative. He ingested encysted Entamoeba coli, strain D, mixed with 

 magnesium oxide. This man has been under observation one year and three 

 and one-half months since this experiment began. Cultures of his stools 

 for amoebae have been constantly negative. Microscopic examinations showed 

 Entamoeba coli in his stools on the eighth day and more or less constantly 

 thereafter. No symptoms of dysentery have developed. 



Experiment XXXIV. — Man 22, aged 31 years, had been under observation 

 in the prison rive years and eleven months. He had not been used previously 

 for experiments. He had a negative dysenteric history. No physical 

 examination of his abdomen was made. Cultural and microscopic examina- 

 tions of his stools for amoeboid organisms were negative. He ingested 

 cysts of Entamceba coli, strain D, mixed with magnesium oxide. This 

 man was under observation ten months after this experiment began. 

 Cultures of his stools for amoebas were constantly negative. Microscopic 

 examinations showed Entamoeba coli in his stools on the eighth day after 

 ingestion and more or less constantly thereafter. No symptoms of dys- 

 entery have developed. 



Experiment XXXV. — Man 23, aged 38 years, had been under observation 



