1923] Kofoid-Swezij: Pcniutrkliomonas ardin deUeUi 385 



The probability that it is concerned both with the motor reaction and 

 ■with the protoplasmic lobe should be borne in mind in the study of 

 these phenomena. 



This lobe is not formed in, nor is it a phase of, the undulating 

 membrane. We have repeatedly watched it in individuals in which 

 the undulating membrane was still functioning. It is formed on the 

 side opposite to that membrane and its rhythm is much slower than 

 that of the membrane. In one observed instance the undulating 

 membrane had a rhythm of 30 beats in 10 seconds while the lobe had 

 one of but 6 beats in the same time. 



SURVIVAL IN WATER 



This parasitic flagellate may survive for some time in liciuid stools 

 at room temperatures. The period of survival in different stools of 

 the same persons is not the same, possibly because of varying bacterial 

 growths. The flagellates often disappear in 3 to 5 days, but in one 

 instance a liquid stool kept at room temperature, 65°-70°, retained 

 living PentatricJwmonas from October -t till October 27, a period of 

 24 days. Sterilized tap water, rain water, and creek water are less 

 favorable for the survival of these flagellates, though not immediately 

 destructive. The flagellates disappear in these fluids within three 

 days following inoculation with fresh stools. This period is sufficient 

 as to length of time for dispersal to and infection of other hosts and 

 may afford a basis for epidemics in cases of infected water supplies. 



In normal saline, three cultures survived for 8, 10, and 15 days 

 respectively. On two vaselined slides at laboratory temperatures, 

 flagellates in a stool diluted with normal saline multiplied and 

 remained active for 5 to 10 days and died out in 13 and 25 days 

 respectively. 



