ENCYSTATION OF ACTINOSPHERIUM EICHHORNI. 409 
mally, I did not obtain satisfactory material. I either allowed 
the cultures to develop too far, or I killed off different, and, 
therefore, non-comparable, stages in the two temperatures. 
I also lost much good material through subsequent inex- 
perienced handling with reagents. Owing to the thickness 
and opacity of the silica coat the cysts are troublesome 
objects to stain and clear. Finally, when I had attained 
some proficiency in treating my material, the cultures began 
to encyst abnormally. I did not succeed in preparing per- 
fectly parallel stages from both sides of a normal culture till 
the beginning of June, and then from Possenhofen material 
fetched in on the 9th of May. After that depression set in, 
and subsequent cultures from the same source were again 
abnormal. 
The material for the April cultures I named A, that used 
from the 10th of May till the 4th of June, B. The following 
table illustrates the course of B cultures: 
Cul- | First day of 
fasten leataeration Fate in warmth (25° C.). | Fate in cold (10° C.). 
i 9 
1 10th May | Attempt at encystation. | Die off without encysting. 
B 
'B 2 llth ,, | Satisfactory encystation. | Majority encyst, but with 
| ' abnormalities. 
| B 3 (14th ,, | 15 animals encyst out of 40. 20 animals encyst out of 40. 
beds Zhe asi 5 oe . eee ova LO 55 35 eo 
| B 5 | 18th ” | ff 29 39 ” 23. 5 ” ” oy) 23. 
1 IB @ Woriln 5 || UB op i. », 20.| Attempt at encystation. 
|B 7 /|29th ,, | None encyst. | None encyst. 
B 8 | 3lst ,, | A few primary cysts formed. | 8 encyst. 
-B 9 | 1st June) Satisfactory encystation. | Satisfactory encystation. 
B10) Qnd ,, | Encyst abnormally. | Die off without encysting. 
| Bll} 4th ,, | Encyst, but witlr some ab- | Attempt at mother cysts. 
normalities. 
| 
That is to say, all cultures except B9 showed some abnor- 
mality in the warmth or in the cold, and sometimes in both. 
For my purpose it was essential that the cysts should be 
normal. B9 was the only culture where I obtained com- 
pletely satisfactory final results. 
