3l6 REUBEN BLUMENTHAL. 



In order to test the narcotic properties of the cyanides, eggs 

 were inseminated and after three minutes, placed in progressive 

 dilutions of KCN and HCN. An A^/ioo,ooo HCN solution still 

 inhibited cell division, while an 7^/30,000 KCN solution was the 

 lowest concentration which would inhibit cell division. Eggs 

 which had been inseminated and then narcotized, were replaced 

 in sea- water and the time for first cell cleavage to appear noted. 

 Eggs which had been exposed to various concentrations of both 

 HCN and KCN for varying lengths of time, were then washed by 

 letting them fall to the bottom of a test tube filled with sea-water 

 and then transferred to sea-water in a watch-glass. These were 

 then inseminated to see \vhether the eggs were still alive after the 

 effects of the cyanides and the hypotonic sea-water. 



The effect of KCN on the permeability was followed merely for 

 comparison with the HCN and ten one-minute readings were 

 taken of eggs in 50 per cent sea-water which had previously been 

 exposed for 25 minutes to concentrations of KCN varying from 

 Nfsoo to N/goo. The KCN solutions were made up entirely 

 with sea-water. 



RESULTS. 



Exposure of Arbacia eggs to HCN causes an increase in the 

 volume of the eggs when placed in hypotonic sea-water, above 

 that of the controls exposed to sea-water. The volume of the 

 eggs varied directly as the concentration of the HCN and as the 

 time of exposure to the HCN solutions. As previously stated, 

 the fact that the HCN solutions were in themselves hypotonic in 

 varying degrees, did not interfere greatly with the final results, 

 since the increase in volume due to this hypotonicity was only 

 slight as compared to the increase in volume due to the HCN. 

 All eggs exposed to the HCN and to the sea-water controls 

 finally reached the same equilibrium point, 4,518 X io 2 ^ 3 - Only 

 eggs which had approximately the same size at the beginning of 

 the experiments, 2,381 X io 2 n 3 , were used. The effect of the 

 HCN was to hasten reaching the equilibrium point. Fig. I, in 

 which the volumes of the eggs after definite exposures to HCN 

 are plotted against the time in the hypotonic sea-water, shows the 

 rate at which the increase in volume occurs. Fig. 2 shows the 



