294 The Philippine Journal of Science isis 



valescent carrier," passing cysts of Entamoeba histolytica in his 

 formed stools. 



Experiment XLIV.— Man 31, aged 36 years, had been under observation 

 in the prison six years and nine months. He had a negative history for 

 dysentery, and had not been used previously for experiments. Physical 

 examination of his abdomen and cultural and microscopic examinations of 

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

 Entamceba histolytica, strain A, second passage, series 1, mixed with 

 magnesium oxide. Cultures of the stool of man 31 following the feeding 

 were negative for amoebae. Microscopic examination of his stool showed 

 Entamoeba histolytica on the fifth day. This man has been under observa- 

 tion one year since the experiment began. The entamoebse have been 

 present in the stools of this man up to the present time, but no symptoms 

 of dysentery have developed. 



Experiment XLV. — Man 32, aged 30 years, had been under observation 

 in the prison four years and eight months. He had a negative history for 

 dysentery, and had not been used for previous experiments. Physical 

 examination of his abdomen and cultural and microscopic examination of 

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

 Entamoeba histolytica, strain A, second passage, series 1, mixed with mag- 

 nesium oxide. Cultures of the stools of man 32 after the ingestion were 

 negative. Microscopic examination of his stools showed Entamoeba histo- 

 lytica on the third day after ingestion and thereafter. This man was 

 under observation five and one-third months after the experiment began. 

 No dysenteric symptoms developed. 



Experiment XLVI. — Man 33, aged 30 years, had been under observa- 

 tion in the prison two years and seven months. He had a negative 

 dysenteric history, and had not been used previously for experiments. 

 Physical examination of his abdomen and cultural and microscopic exam- 

 inations of his stools for amceboid organisms were negative. This man 

 ingested cysts of Entamoeba histolytica, strain A, second passage, series 1, 

 mixed with magnesium oxide. Following the ingestion, cultures of the 

 stools of man 33 were negative. Entamoeba histolytica was found micro- 

 scopically in his stools on the fifth day and thereafter. He has been under 

 observation one year since the experiment began. No symptoms of dys- 

 entery have developed. 



ENTAMCEBA HISTOLYTICA, STRAIN A, SECOND PASSAGE, SERIES 2 



This series of experiments was conducted with strain A which 

 had been passed through man 29 (experiment XLII), who had 

 been parasitized with this strain of Entamoeba histolytica one 

 hundred twenty-one days previously, but who had not, and has 

 not subsequently, developed dysentery. This series of experi- 

 ments, therefore, was made with Entamoeba histolytica from a 

 "contact carrier." 



Experiment XLVII. — Man 36, aged 45 years, had been under observa- 

 tion in the prison eight years and five months. He had a negative 



