322 REUBEN BLUMENTHAL. 



It was shown that HCN is more potent as an anaesthetic than 

 was KCN, since a greater concentration of KCN than HCN is 

 needed to produce anaesthesia. One possible explanation of this 

 follows: KCN in solution is alkaline due to the manner in which 

 it dissociates: 



KCN + H 2 O <=> KOH + HCN. 



K + OH 



Thus it can be seen that a solution of KCN always contains a 

 certain amount of HCN molecules. Therefore the anaesthetic 

 property of KCN may be due to the HCN molecules present in it, 

 but this HCN is partly antagonized, or its effects interfered with 

 by the KOH formed at the same time. Why HCN should cause 

 an increase and KCN a decrease in permeability is as yet problem- 

 atic, unless it is the KOH in the KCN solution which is producing 

 the decrease. It is hoped to gather more data on this point in 

 the future. 



That HCN acts primarily on the cell membrane and not on the 

 interior of the cell, seems likely in view of the fact that eggs, 

 whether treated with HCN or with sea-water, finally reach the 

 same equilibrium point. From recent work Lucke and Mc- 

 Cutcheon (personal communication) state that the velocity of 

 swelling or shrinking of Arbacia eggs in hypotonic or hypertonic 

 sea-water is the same, so that Heilbrunn's objection to calling an 

 increase in the volume of the egg an increase in permeability on 

 the ground that it may be an increase in the extensibility of the 

 membrane, does not seem to hold. We would expect, from his 

 statement, that the eggs would shrink faster than they would 

 swell. 



SUMMARY AND CONCLUSIONS. 



(1) HCN in concentrations varying from N/$oo to N/ 2,000 

 causes an increase in the volume of Arbacia eggs when placed in 

 50 per cent, sea-water, the rate of swelling varying directly as 

 the concentration of HCN and the time of exposure to the HCN 

 solutions. 



(2) KCN in concentrations varying from N/^oo to 7V/9OO 



