296 
IOWA ACADEMY OF SCIENCE Voi.. XXVII, 1920 
was found to be in the neighborhood of 0.015 vol. per cent. On 
the other hand the outcome of fourteen experiments with capryl 
alcohol showed the optimum concentration for the same time of 
exposure to be between 0.035 and 0.045 vol. per cent, which is 
between two and three times the favorable concentration of normal 
octyl alcohol. Table II summarizes a typical experiment using 
normal octyl alcohol of 0.013 vol. per cent concentration. For 
exposures of five minutes duration, this concentration gave the 
best results, and showed very clearly the resistant and susceptible 
phases. 
TABLE II. NORMAL OCTYL ALCOHOL 
Fertilized eggs were subjected for five minutes to 0.013 vol. per cent of 
normal octyl alcohol at intervals of ten minutes. 
Intervals 
AFTER Fer- 
tilization. 
Observed Condition on 
Removal from Fluid 
Observed Condition the 
Following Day 
(1) 15-20m 
Fertilization membrane well 
formed. Slight loss pigment. 
Nearly 50 per cent active blas- 
tulae. Others badly cytolyzed, 
few ruptured. 
(2) 25-30m 
No noticeable cytolysis al- 
though very marked loss of pig- 
ment. 
About 65 per cent active blas- 
tulae. Others cytolyzed. 
(3) 35-40m 
Decided loss of pigment. No 
marked change in membrane 
or cytoplasm^ 
Nearly 80 per cent active. Oth- 
ers intact. 
(4) 45-50in 
About 2 per cent show first 
furrow. Slight loss pigment; 
no cytolysis. 
Practically all active blastulse. 
(5) 55-60m 
Over half in first cleavage. 
About 85 per cent active. 
(6) 65-70m 
About 90 per cent in two-celled 
stage. 
Almost 60 per cent active blas- 
tulae, numbers of two-celled 
eggs present and mostly intact. 
Some badly cytolyzed and rup- 
tured. 
(7) 75-80m 
Aside from loss of pigment no 
noticeable change. 
Between 65 and 70 per cent 
active blastulse. Others cyto- 
lyzed but intact. 
(8) 85-90m 
A few (1 percent) just begin to 
show second cleavage furrow. 
No marked change in appear- 
ance. 
Between 85 and 90 per cent 
active blastulse. Others cyto- 
lyzed but intact. 
CAPRYL ALCOHOL 
As mentioned before, experiments with various concentrations 
of capryl alcohol showed that for brief exposures, the most fav- 
orable concentration was clearly three times that of normal octyl 
alcohol. This may perhaps be accounted for in some measure 
