240 LORANDE LOSS WOODRUFF 
BIV group. About 80 amoebae per cc. were observed on the 
7th day, and from this they gradually decreased until the 18th 
day when the last individuals were seen. 
1000 
Fig.6 £6 II group. The ordinates indicate the number of organisms per cc. 
at the surface. On the abscissa is plotted the number of days of the existence of 
the infusions. Monad =. - - -;Colpoda = - - —; Hypotrichida = — - —; Para- 
maecium = ; Vorticella = — —-; Amoeba = —.-.- —. 
CI group. Amoeba was first seen on the 46th day, reached its 
highest point one day later and maintained this maximum of 
nearly 300 per cc. for five days, after which a slow but steady 
decline brought it to extinction by the 86th day. 
C III group. This form appeared on the 42nd day, reached its 
greatest abundance, 120 per cc., on the following day, and dis- 
appeared by the 53rd day. 
CIV group. In this culture amoebae reached a greater devel- 
opment than in any of the others. They were first seen on the 
6th day and reached 5000 per ce. from the 18th through the 22nd 
day. Then they declined quickly to about 500 per ce. on the 27th 
day, only to rise again almost as fast to their maximum of 5700 
per cc. on the 38th day. From this point they fell to 200 per ce. 
by the 5lst day, and at the last observation, on the 56th day, 
about 1000 per cc. were again present. 
A careful analysis of the above data shows that amoebae 
attained their greatest development slightly later than Paramae- 
cium and earlier than Vorticella at the surface of the infusions. 
