COPPER, ENZYMES, AND FERTILIZATION. 



OTTO GLASER. 

 Amherst College. 



I. Introduction. 



The inhibition of development in Arbacia by infinitesimal quan- 

 tities of copper salts has lately been employed by F. R. Lillie 

 (21 1 ' 2 ) as an expedient in studying the fertilization reaction. The 

 results are highly suggestive and the novelty of the procedure alto- 

 gether likely to inspire much further work. Yet even now there 

 are complications to be dealt with before one can realize on the 

 possibilities which apparently inhere in the method. 



In the first place, there is the matter of effective concentration. 

 This has two aspects : how much of the copper salt added to sea- 

 water actually remains in solution and what proportion of the per- 

 manently soluble fraction reaches the eggs? Moreover, is the 

 chorion involved? There is no reason for thinking that copper 

 would escape concentration in the egg- jelly since, as I have recently 

 shown (22 1 ) this is true of all the salts to which the egg is nor- 

 mally exposed. And, finally, is it possible for a marine organism 

 to carry a " copper-avid substance in the cortex of the egg " and 

 escape the all but inevitable consequence? 



II. The Precipitation of Copper Sulphate in Sea-water. 



The first step was a study of the solubility of copper sulphate in 

 sea-water. Since my program involved reliance on chemical, 

 rather than physiological, means of detection, I employed concen- 

 trations well within the sensitivity range of my first methods. I 

 therefore prepared a standard solution of CuS0 4 .5FLO in dis- 

 tilled water such that each cubic centimeter corresponded to one 

 milligram of the original salt. This was equivalent to .276 mg. of 

 metallic copper per c.c, or Cu^w/230 and w/460. 



This standard was compared colorimetrically with a duplicate 

 solution in sea-water. After correcting for the few drops of 

 ammonia added in order to intensify the blue color, it was found 



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