COPPER, ENZYMES, AND FERTILIZATION. IOI 



this fact at length. Nevertheless we may possibly find along these 

 lines some help in clearing up the uncertainties that now beset us. 

 Very possibly the concentration of copper normally has something 

 to do with checking the growth of the egg, whereas the heightened 

 rate of secretion during fertilization restores conditions essential 

 for further growth and development. No doubt the linkage can 

 be pictured in several ways, but one way is this : the elimination 

 of pigment from the egg might result in the production of fresh 

 pigment, or some other product, which, if copper-avid, might also 

 draw upon the copper of the enzymes and thus assist in the process 

 of activation. 



All this, however, is merely in the realm of possibilities. At 

 the rate at which discoveries are being made in this field hardly 

 anyone would wish to formulate a theory of fertilization. The 

 process is far more complicated than it seemed ten years ago, and 

 if one thing is more certain than another, it is that the major 

 classes of evidence have not yet been handed in. 



XIII. Summary, 

 i. Nearly 37 per cent, of the copper sulphate added to sea-water 

 is precipitated at once when the concentration is Cu = m/46o. 



2. Two tenths c.c. normal Arbacia eggs in 75 minutes reduce the 

 concentration of 14.8 c.c. of a Cu solution from w/ 1,460 to 

 m/i, 790.9. 



3. In this reduction the egg jelly or chorion is heavily involved. 



4. It was impossible to determine the quantities of copper ab- 

 sorbed by normal eggs and eggs without jelly because of an appar- 

 ent secretion of copper by the eggs themselves. 



5. Therefore, the demonstration of copper in Arbacia eggs was 

 undertaken. The copper was identified as cupric hydroxide, cupric 

 cyanide, cupric ferrocyanide, copper xanthate, crystalline cupric 

 sulphate, as metallic copper on tin-foil and aluminum, and finally 

 by electrolytic precipitation under conditions under which copper 

 and only copper could be deposited. 



6. The copper was localized in the egg directly by means of 

 hematoxylin and the triple-nitrite of potassium-copper and lead. 

 Indirectly it was localized by the analysis of egg secretions. 



7. The copper occurs chiefly in the egg pigment; the vitelline 



