STUDIES OF FERTILIZATION, X. 



THE EFFECTS OF COPPER SALTS ON THE FERTILIZATION 



REACTION IN ARBACIA AND A COMPARISON 



OF MERCURY EFFECTS. 



FRANK R. LILLIE, 



THE UNIVERSITY OF CHICAGO. 



i. INTRODUCTION. 



Copper salts are known to have a profoundly injurious effect 

 on many organisms even in high dilutions. They are also known 

 to form compounds with ferments and proteins (on one side of 

 the isoelectric point). It might therefore be expected in advance 

 that they would have very definite effects in the delicate reactions 

 of fertilization, which might be used advantageously in the 

 analysis of these reactions, the precise character of which is still 

 a matter of dispute. 



The results reported were obtained in the summers of 1920 

 and 1921 at the Marine Biological Laboratory at Woods Hole. 

 They have led me to the conclusion that the fertilization reactions 

 in the sea-urchin are due primarily to activation of a ferment- 

 like substance contained in the cortex of the egg which is pre- 

 sumably identical with the fertilizin of my earlier studies. The 

 method of approach is quite new in fertilization studies, but has 

 been previously used in ferment studies, as I discovered after 

 the conclusion of my experiments. Certain points of comparison 

 between inactivation of ferments by salts of heavy metals and 

 inactivation of the fertilization reaction were found. 



As soon as we adopt the conclusion that fertilization is essen- 

 tially activation of a substance, contained in the cortex of the 

 egg, by the spermatozoon (Lillie, 1914, 1919), the way is open 

 for study of the properties of this substance by means of inhibitors 

 of fertilization in general. If we were to determine the quali- 

 tative and quantitative range of such inhibitors we would be in 

 possession of a list of properties of the postulated substance that 



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