VIII, B, 4 Walker and Sellards: Entamoebic Dysentery 265 



Table I. — Strains of amoebae used in feeding experiments. 



Strain 

 No. 



Source. 



Locality. 



Species. 



Feedings. 



1 

 2 

 3 

 4 

 5 

 6 

 7 

 8 

 9 

 10 

 11 

 12 

 13 





Manila, P.I 



A 

 A 

 B 



2 

 3 

 1 

 1 

 2 

 1 

 1 

 1 

 1 

 3 

 1 

 2 

 1 



do 



do- 



do 



do 







U. S. A 



C 



Hay — 



Illinois, U. S. A 



D 



E 

 F 

 A 

 F 

 G 

 G 

 H 

 F 



Algse - 



Kansas, U. S. A 





Manila, P. I _ 



do 



do — 



do 



do 



Diarrhoea! stool 



Kansas, U. S. A 



Manila, P. I 



do 



do 



do 



do _- 



Total 





8 



20 







To these 8 distinct species of Amoeba no names have been 

 given, since to do so in the present chaotic state of the nomen- 

 clature of the free-living amoebae would only add to the confusion. 

 Species A, B, F, G, and H are illustrated in the plates of an earlier 

 paper by one of us (Walker, 1911), Among these 13 strains 

 of amoebae are represented all of the different species that could 

 be cultivated from the Manila w^ater supply, from normal stools, 

 and from dysenteric stools in Manila. A larger series of ex- 

 periments w^ith cultures from dysenteric stools was not con- 

 sidered necessary, in view of the behavior of all of the amoebse 

 in the intestinal tract of man. 



The amoebae fed in these experiments were cultivated on a 

 medium which had the following composition: 



Agar-agar 

 Sodium chloride 

 Liebig's beef extract 

 Normal sodium hydroxide 

 Distilled water 



2.5 grams 

 0.05 gram 

 0.05 gram 



2cc. 

 100 cc. 



Without clarifying, it was sterilized at 7 kilograms' pressure 

 per square centimeter for about three-quarters of an hour. 

 After the sterilization, its reaction was neutral to phenolphtha- 

 lein. This medium, which is essentially that of'Musgrave and 

 Clegg (1904), has proved satisfactory, all of the amoebae grow- 

 ing well upon it. 



The cultures of amoebae used in the feeding experiments were 

 pure with reference to the protozoon ; that is, they consisted of a 

 single species of Amoeba, but they were cultivated with the 



