VIII. B, 4 Walker and Sellards: Entamcebic Dysentery 273 



amoeboid organisms were negative. He ingested the growth on 4 agar- 

 slant cultures of Aniceba lOG, isolated from a dysenteric stool in Kansas, 

 mixed with magnesium oxide. The cultures ingested by this man con- 

 tained motile forms of the amoeba exclusively. Amoeba G was recovered 

 in cultures of this man's stools on the sixth day only after feeding. Micro- 

 scopic examinations of his stools for amogboid organisms have been con- 

 stantly negative. He has been under observation two years and four and 

 one-half months since this experiment began. No symptoms of dysentery 

 have developed. 



Experiment XVII. — Man 5, aged 30 years, had been under observation 

 in the prison for six years and nine m.onths. He gave a history of mucous 

 dysentery seven years ago. He had not been used for previous feeding 

 experiments. Physical examination of his abdomen and microscopic and 

 cultural examinations of his stools for amoeboid organisms were negative. 

 He ingested the growth on 3 Petri-plate cultures of Amoeba llG, mixed 

 with magnesium oxide. This amoeba was isolated in culture from a man 

 suffering from an acute attack of entamcebic dysentery. The culture fed 

 contained only encysted forms. Transplant cultures made to test the 

 viability of the cysts all showed a growth of Amoeba G. Cultures of this 

 man's stools showed a growth of Am,ceba G on the first, second, and third 

 days after feeding, but never subsequently. Microscopic examinations of 

 his stools have been constantly negative. This man has been under observa- 

 tion two years and six and one-half months since this experiment began. 

 During this time amoeboid organisms were never found microscopically or 

 culturally in his stools, and he has never exhibited any symptoms of 

 dysentery. 



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

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

 mucous stools for four months, two years ago. He had not been used for 

 previous feeding experiments. Physical examination of his abdomen and 

 microscopic and cultural examinations of his stools for amoeboid organisms 

 were negative. He ingested the growth on 4 Petri-plate cultures of 

 Amosba 12II, unmixed with other substance. This amoeba was isolated in 

 culture from a dysenteric stool. The cultures ingested contained both mo- 

 tile and encysted forms of the amoeba. Transplant cultures made to test 

 their viability showed a luxuriant growth of Amoeba H. Cultures of this 

 man's stools on Musgrave and Clegg's medium showed a grovifth of Amoeba 

 H on the first day after feeding, but never subsequently. Microscopic 

 examinations of his stools have been constantly negative. This man was 

 under observation one year and five months following the beginning of this 

 experiment. During this time Amoeba H has never been found micro- 

 scopically in his stools, and he has never shown any symptoms of dysentery. 



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

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

 bloody mucous dysentery for four months, two years ago. He had been 

 used sixteen days previously for another feeding experiment with the 

 same strain and species of amoeba, with negative result (experiment 

 XVIII). Physical examination of his abdomen and microscopic and cul- 

 tural examinations of his stools for amoeboid organisms were negative. 

 This man ingested the growth on 4 Petri-plate cultures of Amoeba 12H, 

 cultivated from a dysenteric stool, mixed with magnesium oxide. The cul- 

 tures ingested by this man contained encysted amoebae only. Transplant 



