PROCESS OF REGENERATION 103 



blood in cyanide poisoning is abnormally high. Geppert there- 

 fore concluded that cyanogen reduces the capacity of the cells 

 to use oxygen. This conclusion is supported by the experiments 

 of Warburg ('10), of Loeb ('06 a, '06 b, '10 a, '10 b), and of Loeb 

 and Wasteneys ('10, '11, '13 a, '13 b), who found that the oxygen 

 consumption of eggs and other cells is decreased in the presence 

 of cyanides; of Schroeder ('07) who obtained the same result 

 with Aspergillus; and of Vernon ('06) who showed that the oxy- 

 gen consumption of a perfused kidney is diminished when cyan- 

 ides are present in the perfused fluid; and I myself, working witli 

 sponges, have recently demonstrated to my entire satisfaction 

 that the oxygen consumption of these animals is invariably 

 lowered when potassium cyanide is present in the sea water, 

 even in concentrations as low as xs^o o-' The cyanides also ha\'e 

 a general depressing effect on enzymatic processes, and on many 

 chemical actions, oxidative and otherwise. On the other hand, 

 there have not been wanting objections to the idea that the 

 cyanides inhibit oxidations; principal among these is the state- 

 ment that the cyanides are equally poisonous to tissues and 

 organisms which are not affected by the absence of atmospheric 

 oxygen ,as the nerve cord of the Limulus heart (Carlson, '07), and 

 anaerobic bacteria. In reply to this, it may be suggested that 

 the series of chemical processes which we call oxidation is probably 

 much the same up to a certain point in both aerobic and anaerobic 

 organisms, and it is these initial reactions which the cyanide affects 

 (Matthews, '05). 



Direct evidence that the susceptibility to cyanide runs parallel 

 with the rate of metabolism has been furnished by Child ('13 aj, 

 who has experimentally determined the following facts : 



1. Animals stimulated to motor activity are more susceptible 

 than quiescent ones. 



2. The susceptibihty increases with rising temperature; and 

 the temperature coefficient of susceptibility is the same as the 

 usual temperature coefficient for chemical reactions in general. 



3. Other forms of stimulation (as injury, cutting the animal 

 into pieces) increase the susceptibility to cyanide. 



^ These results will be published shortly. 



