354 A - w - BELLAMY. 



or intensities of action, do tend to obscure the differential sus- 

 ceptibility relations, may be used in other concentrations or 

 intensities, to produce differential inhibitions that, in kind, are 

 not different from the differential inhibitions produced in a 

 variety of other agents. 



Although it was stated (p. 346) that in the reaction of the 

 frog egg to the different substances used to modify development, 

 no evidence was found of any "specific" action, in the sense in 

 which the term has been used, I do not wish to be understood as 

 implying that all chemical substances act upon protoplasm in 

 exactly the same way. It is to be expected, and bio-chemical 

 and zoological literature contain abundant evidence to show, 

 that different agents do affect protoplasm in different ways. 

 KNC, e.g., which is a powerful reducing agent is known to 

 interfere with oxidations and enzyme activity in the organism. 

 Hyman (1919) found that in planaria oxygen consumption may 

 be reversibly cut down as much as 80 per cent, to 90 per cent., 

 in the presence of minute amounts of KNC. In this paper she 

 gives a comprehensive review of the literature on the action of 

 cyanides on protoplasm so that further discussion of this matter 

 is unnecessary here. So far as susceptibility relations are con- 

 cerned formaldehyde appears to affect protoplasm in much the 

 same way as KNC, and KMnC>4 which is a vigorous oxidizing 

 agent is equally efficient for demonstrating differences in suscepti- 

 bility in organisms. 1 It is a significant fact that these oxidizing- 

 and reducing agents are among the most effective agents that 

 have been used in the study of physiological axiation. 



As regards anesthetic action in the stricter sense, whether these 

 agents disturb oxidations, affect the lipins of the cell, produce 

 changes in the surface membranes, etc., there appears to be no 

 consensus of opinion. 



Various salts affect protoplasm, especially the colloid sub- 

 stances, in widely different w r ays. They may bring about 

 changes in the state of aggregation of colloids, and the loss or 

 addition of water; induce changes in ionization which may 

 result in the precipitation or solution of certain substances in 

 the protoplasm; or upset the electrical equilibrium, and so on. 



Acids and alkalies also affect the speed and type of many 

 Child, BIOL. BULL., 36, 1919. 



