XXVI 
ON THE NATURE OF THE PROCESS OF FERTILIZA- 
TION AND THE ARTIFICIAL PRODUCTION OF NOR- 
MAL LARV4 (PLUTEI) FROM THE UNFERTILIZED 
EGGS OF THE SEA-URCHIN' 
1. Former researches had led me to suspect that changes 
in the state of matter (liquefactions and solidifications) might 
play an important réle in the mechanics of life-phenomena. 
While studying the absorption of liquids by muscle I found 
that, to all appearances, a } solution’ of CaCl, favors the 
formation of solid compounds in the muscle, while an equi- 
molecular solution of KCl favors the formation of more 
liquid compounds. Na ions rank between the K and Ca 
ions. In these phenomena, however, much depends upon 
the concentration of the salts. We know that the enzymes 
of coagulation and liquefaction are greatly influenced in 
their action by the Ca, Na, K, and Mg ions. Ca favors 
coagulation, and Mg does the reverse. Between these come 
the two other ions. In this case also much depends upon 
the concentration. 
I have made a series of studies on the mechanics of life- 
phenomena, which will be published shortly in this Journal. 
I wish now to deal only with one part of these studies, 
namely, that referring to the nature of the process of fertili- 
zation. 
I found that in $n solutions® of CaCl,, NaCl, KCl, and 
MgCl, the segmentation of fertilized eggs of sea-urchins 
1 American Journal of Physiology, Vol. III (October 1, 1899), p. 135. 
2I propose to substitute in the future the % solution of NaCl for the 0.7 per 
cent. solution. Itis time that we were rid of percentage solutions in physiology. 
%s Approximately the concentration of sea-water. 
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