VIII, B, 4 Walker and Sellards: Entamoehic Dysentery 269 



Experiment VI. — Man 7, aged 30 years, had been under observation in 

 the prison for five years and nine months. He gave a history of 3 attacks 

 of dysentery, each of one week's duration, six years ago. He had been 

 used for 3 previous feeding experiments (experiments XI, XIH, and XVI), 

 the last of which was ninety-two days previously, and all of which were 

 followed by negative results. Physical examination of his abdomen and 

 microscopic and cultural examinations of his stools for amoeboid organisms 

 were negative. He ingested the growth on 7 Petri-plate cultures of 

 Amoeba SB, mixed with magnesium oxide. Amoeba B was the second of 2 

 species which had been isolated in culture from the Manila water supply. 

 The cultures ingested by this man consisted exclusively of encysted 

 amoebae. Transplant cultures made to test the viability of the cysts showed 

 an abundant growth of amcebas. Amoeba B was recovered in cultures 

 from the stools of this man from the first to the fifth day after ingestion 

 but never subsequently. Microscopic examination of his stools for amoeboid 

 organisms have been constantly negative. This man has been under 

 observation two years and one and one-half months since this experiment 

 began. No symptoms of dysentery have developed. 



Experiment VII. — Man 2, aged 40 years, had been under observation 

 in the prison four years and ten months. He had a negative dysenteric 

 history, and 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 1 agar-slant culture of Amoeba iC, mixed with magnesium oxide. 

 Amoeba C was isolated from clover grown in the United States. The 

 culture ingested was an old one containing only encysted amoebae. A 

 transplant culture made from this culture to test the viability of the cysts 

 gave an abundant growth of Amoeba C. Following the feeding, cultures 

 and microscopic examinations of his stools for amoeboid organisms were 

 constantly negative, and no dysenteric symptoms developed. He was under 

 observation one hundred twenty-six days when he was used for a feeding 

 experiment with Entam,oeba histolytica (part IV) and developed dysentery 

 on the twentieth day with Entamoeba histolytica in his stools. Altogether, 

 this man has been under observation two years and seven months, during 

 which time Am^oeba C has never been found culturally or microscopically 

 in his stools. 



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

 in the prison for seven years and eight months. He had a history of 1 

 attack of dysentery of one month's duration eight 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 organism were negative. He ingested the growth on 2 Petri- 

 plate cultures of Amoeba 5D, mixed with magnesium oxide. Amoeba D 

 had been isolated in culture from an infusion of hay coming from Illinois, 

 United States. The cultures fed to this man contained encysted amoebae 

 only. Transplant cultures made to test the viability of the cysts showed an 

 abundant growth of Amoeba D. Following the ingestion, cultures of the 

 stools of this man showed a growth of Amoeba D on the first day after feed- 

 ing, but never subsequently. Microscopic examinations of his stools have 

 been constantly negative. This man has been under observation two years 

 and five and one-half months since this experiment began, but has never 

 shown any symptoms of dysentery. 



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