292 IOWA ACADEMY OF SCIENCE Vor.. XXVII, 1920 
TABLE I. 1-AMYL ALCOHOL 
July 16, 1 :45 P.M. The fertilized eggs were placed in 50 c.c. of 0.9 vol. 
per cent i-amyl alcohol, at the intei*vals after fertilization noted in column 
1. All exposures except the first (1) (6 minutes) were of eight minutes 
duration 
Intervals 
AFTER Fer- 
tilization 
Observed Condition of the 
Eggs at the Time of Removal 
from Solution 
Proportion Forming Blastu- 
AND Conditions of Re- 
maining Eggs Next Day 
(1) 3-9m 
Fertilization-membranes well 
formed. No marked cytolytic 
change noted. 
About 5 per cent form free- 
swimming blastulae. Consider- 
able numbers cytolyzed. 
(2) 10-18m 
No marked change in appear- 
ance. Uniform. 
About 10 per cent form blastu- 
Ise. Not so badly cytolyzed; 
most cells intact. 
(3) 20-28m 
Membranes markedly swollen 
in some cases. Slight fading 
of pigment. 
Nearly 30 per cent free-swim- 
ming blastulae. Most eggs in- 
tact. 
(4) 30-38m 
A few cells plasmolyzed, other 
membranes markedly swollen. 
Between 30 and 40 per cent 
free-swimming blastulae. Most 
others intact but swollen. 
(5) 40-48m 
No marked change. Faint in- 
dication of cleavag'e furrow in 
a few scattered cells. 
Large majority (75 to 80 per 
cent) form swimming blastulae. 
(6) 50-58m 
About 65 per cent in two-celled 
stage. -Others intact. 
Relatively few (less than 10 
per cent) form surviving blas- 
tulae. 
(7) 60-68m 
About 90 per cent in two-celled 
stage. Others intact. 
Between 30 and 35 per cent 
form blastulae. 
(8) 70-78m 
Practically all in two-celled 
stage. 
Few (15 to 20 per cent) form 
blastulae. Others intact. 
(9) 80-88m 
A few are starting second 
cleavage furrow. 
3 to 5 per cent form blastulae. 
Others intact. 
sively declines up to the end of forty-eight minutes (just before 
the first cleavage). There then follows a very susceptible period 
just at the time of cleavage. Later the resistance phase reappears 
until about the time of the second cleavage. If the time intervals 
are plotted as abscissae, and the percentage of surviving blastulae 
as ordinates, the relationships may be represented in the curve 
shown below (Fig. 50). 
HEXYL ALCOHOL 
In exploring the range of suitable concentrations for hexyl 
alcohol, the next higher member of the series, assuming that it 
should be approximately three times as effective as i-amyl alcohol, 
three preliminary experiments were performed. For these, solu- 
