186 W. C. ALLEE 



IV. METABOLISM AND RHEOTAXIS 



Child ('15 and citations) has estabhshed a relationship be- 

 tween the metabolic rate of many lower animals and plants 

 and their resistance to potassium cyanide. Hyman ('16, 16a) 

 obtained similar results for certain annelids and sponges and 

 I have found that this relationship holds for Asellus ('14). Gep- 

 pert ('89) for certain mammals and birds, Warburg ('10), Loeb 

 and Lewis ('02), Loeb ('06) and Loeb and Wasteneys ('10, '13) 

 for sea urchin eggs found that the addition of cyanide decreased 

 markedly the oxygen consumption; Hyman ('16 a) gives more 

 detailed results of this relationship with sponges. It appears 

 more than probable that the cyanide acts by affecting the oxida- 

 tions but as Child ('14) says: 



Susceptibility to cyanide in concentrations which are lethal within 

 a few hours varies with the general rate of metabolic activity or of 

 certain fundamental n;etabolic reactions. This conclusion holds 

 whether the cyanide acts more or less directly upon oxidations or upon 

 the condition of the metabolic substratum or certain of its constituents 

 and so indirectly upon metabolism in general. 



Does resistance to sodium cyanide measure the metabolic rate of 



Asellus? 



Certain observations that isopods much depressed by treat- 

 ment with calcium chloride became more active after being 

 put into N/1000 potassium cyanide and that isopods from potas- 

 sium chloride did not, led to a fear that the cation even in this 

 dilution might have some effect on the death point, particularly 

 with isopods previously treated with either of the above salts. 

 For this reason it was thought desirable to substitute sodium 

 cyanide with its less toxic and less stimulating cation. The 

 expectation was not entirely realized for animals treated with 

 calcium chloride until they had lost power to move regained it 

 slightly in sodium cyanide. It is possible that the cyanide 

 itself causes a slight initial stimulation (Loevenhart '06), Hyman 

 ('16 a). 



The use of sodium in place of potassium cyanide required a 

 retesting to determine what strength, if any, would measure 



