THE EFFECT OF CYANIDES ON PROTOPLASM. 319 



or minimum volumes respectively, were returned to sea-water 

 and fertilized. Cell division took place, showing that the eggs 

 were alive at their greatest expansion or contraction. One cannot 

 very well tell whether an anaesthetized egg can be fertilized 

 while in that condition, since a normal egg does not show first 

 cleavage until about 60 minutes after insemination. Within 

 these 60 minutes, the narcotized condition may have been re- 

 versed, and the dividing egg be, not a narcotized egg, but a normal 

 one. The anaesthetized egg, however, did form a fertilization 

 membrane immediately after insemination, and in view of the 

 statement which follows, might indicate that a narcotized egg 

 can be fertilized, but cleavage is delayed until the narcotic has 

 diffused out of the egg, or until the narcotized condition has been 

 reversed. Untreated eggs normally showed first cleavage about 

 60 minutes after insemination. Eggs which had been anaesthet- 

 ized with varying concentrations of HCN 3 minutes after insemi- 

 nation and then transferred to sea water, showed first cleavage at 

 varying times always longer than the untreated egg; however, 

 the higher the concentration of HCN used to anaesthetize them, 

 the longer it took for first cell cleavage to appear. 



Lillie ('16) has suggested a modification of the equation 

 followed by unimolecular reactions dx/dt = k(a -- x), in dealing 

 with rates of osmotic pressure in egg cell, of the form 



kt = Ln-^- where V eq is volume at equilibrium; F is 



V eg ' V t 



volume at the first instant (in sea-water); and V t is the volume 

 at time /. Lillie found that this equation represents the rate of 

 swelling of fertilized and unfertilized Arbacia eggs in hypo tonic 

 sea-water and Lucke and McCutcheon ('26) found that it ap- 

 plied also to the rate of swelling in sea-water of varying hypo- 

 tonicity. 



That this same equation holds good in the series of experiments 

 described in this paper, can be seen from Fig. 4. When log 



V eq VQ . 



is plotted against time in nypotonic sea- water, a 



V eg 



straight line should result. This has been found to be the case. 

 The values of k, the velocity constant, are given by the slope of 

 the line. This figure shows that the higher the concentration of 



