282 The Philippine Journal of Science wis 



man has been under observation two years and five montlis since this ex- 

 periment began. Cultures of his stools on Musgrave and Clegg's medium 

 for amoebas have been constantly negative. Microscopic examination showed 

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

 thereafter. No symptoms of dysentery have developed. 



Experiment XXVI.— Man 14, aged 24 years, had been under observation 

 in the prison seven years and seven months. He had not been used pre- 

 viously for experiments. History and physical examination of his abdomen 

 and microscopic and cultural examinations of his stools for amoeboid organ- 

 isms were negative. He ingested cysts of Entamceba coli, strain B, which 

 had been kept at room temperature two days, mixed with powdered starch. 

 This man was under observation one year and three months after this 

 experiment began. Cultures of his stools on Musgrave and Clegg's medium 

 were constantly negative. Microscopic examination showed Entamoeba 

 coli in his stools on the first day after ingestion and more or less constantly 

 thereafter. No symptoms of dysentery have developed. 



Experiment XXVII. — Man 15, aged 25 years, had been under observation 

 in the prison seven years and four months. He had not been used pre- 

 viously for experiments. His history with reference to dysentery was 

 negative. Physical examination of his abdomen was not made. Micro- 

 scopic and cultural examinations of his stools for amoeboid organisms were 

 negative. He ingested cysts of Entamoeba coli, strain B, which had been 

 kept at room temperature for two days, mixed with powdered starch. This 

 man has been under observation one year and eight months since this 

 experiment began. Cultures of his stools on Musgrave and Clegg's medium 

 were uniformly negative. Microscopic examinations showed Entamtsba coli 

 in his stools on the eleventh day and more or less constantly thereafter. 

 No symptoms of dysentery have developed. 



Experiment XXVIII. — Man 16, aged 26 years, had been under observa- 

 tion in the prison six years and five months. He had not been used pre- 

 viously for experiments. His history with reference to dysentery was 

 negative. No physical examination was made of his abdomen. Micro- 

 scopic and cultural examinations of his stools for amoeboid organisms were 

 negative. He ingested encysted Entamceba coli, strain C, mixed with 

 magnesium oxide. Since this experiment began this man has been under 

 observation one year and six months. Cultures of his stools on Musgrave 

 and Clegg's medium have been constantly negative. Microscopic examina- 

 tions showed Entamceba coli in his stools on the first day and more or less 

 constantly thereafter. No symptoms of dysentery have developed. 



Experiment XXIX. — Man 17, aged 30 years, had been under observation 

 in the prison five years and five months. He had suflrered from 2 attacks 

 of entamoebic dysentery four years and seven months and one year and 

 five months previously, respectively. No physical examination was made 

 of his abdomen. Cultural and microscopic examinations of his stools for 

 amoeboid organisms were negative. He ingested cysts of Entamoeba coli, 

 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 examinations of his stools 

 were also negative; that is, this man failed to become parasitized with 

 Entamoeba coli. No symptoms of dysentery developed. 



Experiment XXX. — Man 18, aged 32 years, had been under observation 

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



