508 
ZOOLOGY: R. ERDMANN 
DESCRIPTION or EXPERIMENTS 
The following short description of three typical experiments from a 
series of thirteen which were performed from September 25, 1914 to 
April 27, 1915, indicates that Trypanosoma brucei in slide plasma 
cultures undergoes different changes when maintained at a temperature 
identical with that of the mammalian blood (37°C.) from those which 
they undergo when maintained at a temperature (16°-18°C.) com- 
parable with that of an invertebrate host. 
d I e l I 
Fig. 7 
Strain M, October 12 to 19, 1914, Culture kept at J7°C.— For this 
experiment the trypanosomes used resembled those of figure 1, animals 
f and g. The rat had been inoculated 84 hours, and died 2 hours after 
the experiment began. In figure 2, a trypanosome is pictured which 
has been six hours in the plasma medium. It was stained, after fix- 
ation with Schaudinn's fluid, with Giemsa feucht. This animal has the 
typical aspect of a trypanosome and proves that trypanosomes can 
live and divide in plasma at least six hours without changing their typi- 
cal forms. Incidentally it has been observed in dividing forms just 
mentioned that the nuclear division lasts 2\ hours. 
After having been subjected to the plasma for 24 hours the trypano- 
somes divide more rapidly. One organism frequently produces four 
