268 MORRIS Ss. FINE 
presence, initially, of as large a number of representative proto- 
zoan forms as possible. 
Atypical member. Infusion D-1 was prepared exactly as the 
above with the exception that the water to which the boiled hay 
and infusion were transferred had been heated to about 90° C. 
and no protozoa were introduced. By this means was obtained 
a protozo6n-free culture fluid.’ 
Series B: Typical members. Infusions B-1, B-2, B-21, B-22, 
B-31, B-32, B-41, and B-428 were prepared by boiling 20 grams 
Timothy hay for five minutes, just as in series A, and then strain- 
ing into unboiled water so that a final volume of 5 liters was 
obtained. These were seeded exactly as in series A. 
Atypical members. Infusion E-1 was prepared just like the 
typical members of this series except that the water into which 
the boiled infusion was strained had been raised to a temperature 
of 90° C. We have thus a protozoén-free infusion ‘of series B, 
just as D-1 is a protozoén-free infusion of series A. Infusions 
BB-1, BB-2, BB-3, BB-4, BB-5, and BB-6 were prepared exactly 
like the typical members of this series but in addition were treated 
in various ways. BB-1 and BB-2 were left unchanged, serving 
as controls. To BB-3 and BB-4 were added 5 and 20 grams of 
dextrose respectively. BB-5 was kept practically neutral to 
phenolphthalein by adding, when necessary, the calculated 
amount of NaOH. This necessitated stirring at each addition 
of alkali, and hence, as a check, BB-6 was stirred at the same time. 
Series C: Typical members. Infusions C-1, C-2, C-3, C-3]1, 
C-41, C-42, and M-1 each consisted of 20 grams unboiled hay with 
5 liters unboiled water. To this was added a small amount of 
seed. With certain exceptions, mentioned elsewhere, the hay 
was kept continuously at the bottom of the infusion. 
Atypical member. Infusion 8-1 was prepared by heating 20 
grams of dry hay in an autoclave and adding 5 liters of water 
which had been warmed to 90° C. S-1 is therefore a protozoén- 
free infusion of series C. 
7 No attempt was made subsequently to keep the infusion free from bacteria. 
8 Infusions B-41 and B-42 were subjected to a chemical examination so infre- 
quently that the results are omitted from table 3. 
