VIII, B, 4 Walker and Sellards: Entamcebic Dysentery 281 



negative. He ingested cysts of Entamoeba coli, strain A, mixed with 

 magnesium oxide. This man has been under observation two years since 

 the experiment began. Following the feeding, cultures of this man's stools 

 were constantly negative. Microscopic examinations showed Entamoeba 

 coli in his stools on the fourth day after feeding and more or less constantly 

 thereafter. No symptoms of dysentery have developed. 



Experiment XXII. — Man 6, aged 27 years, had been under observation 

 in the prison for five years and seven months. He gave a history of a 

 bloody mucous dysentery of four months' duration two years ago. He had 

 been used previously for 1 feeding experiment with a culture of amcebse, 

 which was followed by negative results (experiment XVIII, part II). 

 Physical examination of his abdomen and microscopic and cultural examina- 

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

 encysted and motile Entamoeba coli, strain A, mixed with magnesium oxide. 

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

 experiment began. Following the ingestion, cultures of this man's stools 

 were constantly negative for amoeboid organisms. Microscopic examina- 

 tions showed Entamoeba coli in his stools on the seventh day and more or 

 less constantly thereafter. No symptoms of dysentery have developed. 



Experiment XXIII. — Man 8, aged 57 years, had been under observation 

 in the prison seven years and nine months. He gave a history of 1 attack 

 of dysentery of one month's duration eight years ago. He had been used 

 for 1 feeding experiment with a culture of amoebae with negative results 

 (experiment VIII, part II). Physical examination of his abdomen and 

 microscopic and cultural examinations of his stools for amoeboid organisms 

 were negative. He ingested cysts of Entamoeba coli, strain A, which had 

 been kept at room temperature for ten days, mixed with powdered starch. 

 This man has been under observation two years and five months since this 

 experiment began. Cultures of his stools were constantly negative. Mi- 

 croscopic examination showed Entamcsba coli in his stools on the seventh 

 day and more or less constantly ever since. No symptoms of dysentery 

 have developed. 



Experiment XXIV. — Man 12, aged 44 years, had been under observation 

 in the prison for seven years and eight months. He had not been used for 

 previous experiments. He had a negative dysenteric history. Physical 

 examination of his abdomen and cultural and microscopic examinations 

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

 Entamoeba coli, strain A, which had been kept at room temperature ten 

 days before use in this experiment, mixed with powdered starch. This 

 man was under obsex'vation one year and ten months after this experiment 

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

 constantly negative for amoebae. Microscopic examinations showed Enta- 

 moeba coli in his stools on the second day and more or less constantly 

 thereafter. No symptoms of dysentery have developed. 



Experiment XXV. — Man 13, aged 48 years, had been under observation 

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

 viously for experiments. He gave a history of 1 attack of dysentery of 

 one week's duration twenty years ago. Physical examination of his ab- 

 domen showed a sigmoid that was palpable, firm, and smooth. Micro- 

 scopic and cultural examinations of his stools for amoeboid organisms were 

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

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



