414 



RELATIVE TOXICITY OF HALIDES 



were noted at which the hearts ceased to respond to electrical stimu- 

 lation (the times at which normal heart beat ceased were irregular), 

 and the muscles ceased to respond to such stimulation applied (a) 

 directly, and (b) through their nerves. In all cases it was found that 

 nerve tissue died shortly before the death of the corresponding 

 muscle. 



TABLE I. 



Composition of Modified Locke Solutions. 



Water to 1 ,000 cc. 



It was observed very early in the experiments that a difference of 

 a few degrees of temperature had a marked effect on the duration of 

 life of the muscle-nerve preparations, in whatever solutions they were 

 immersed. This is in agreement with previous observations of 

 Cameron andBrownlee (1915-16) (Table II), while Gunn and Under- 

 bill (1914-15) have shown that temperature produces a similar effect 

 in surviving mammalian tissue (intestine) . Utilizing the fairly stable 

 temperature conditions of the city water supply through the long 

 winter here, it was possible to obtain observations throughout which 

 the temperature remained fairly constant at 5°C. The shallow 

 beakers containing the preparations were immersed in a large sink 

 through which water from the city main flowed constant, and in 

 most of the experiments the solution temperatures were thus kept 

 constant to 5° ± 1°C. By selecting suitable times experiments at 



