700 RALPH S. LILLIE 
mal. Usually a small proportion of such eggs develop to the 
blastula stage; such blastulae are, as a rule, feeble and more or 
less abnormal; the proportion so developing is variable and always 
small—a fraction of one per cent. The four salts NaI, NaCNS, 
KI, KCNS all produce essentially the same result; NaCNS how- 
ever has proved somewhat less effective as well as less toxic than 
the others. Nitrate produces membranes and change of form in 
a smaller though still considerable proportion of eggs, varying 
from ten to fifty per cent. Chlorate is less effective than nitrate 
and shows little action, though decidedly more than bromide. 
The differences between sodium and potassium salts have proved 
indecisive. 
Even in the most favorable experiments the great majority of 
eggs treated in the above manner merely undergo some change 
of form or show a few irregular cleavages and then die and disin- 
tegrate. Next day they are typically found dead, coagulated, and 
decolorized, with a few exceptions. Brief exposure to isotonic 
iodide and sulphocyanate solutions has in fact an effect upon the 
eggs essentially similar to that produced by weak solutions of 
fatty acids or other. membrane-forming substances. It is signifi- 
cant that after twenty-four hours the eggs in these cultures are 
typically free from pigment, indicating that the permeability 
has remained permanently greater than normal. The toxic 
effect of the treatment is, I believe, due essentially to the persist- 
ence of this condition of abnormally increased permeability. 
Cytolysis hence follows in course of time. 
Invariably the eggs treated with the pure and those treated 
similarly with the calecium-containing solutions present astrik- 
ing contrast. The above effects are in the great majority of eggs 
entirely prevented by the presence of calcium chloride in-the 
proportions named below. The eggs remain round and unaltered 
with a few exceptions, especially in sulphocyanate solutions— 
showing no sign of membrane-formation or change of form, and 
next day almost all remain living and on fertilization with sper- 
matozoa largely develop into normal larve. It should be added 
that the action of sulphocyanate is less completely counteracted 
by calcium than that of nitrate and iodide, though with all salts 
the above contrast is strongly marked. 
