1909.] Physiological Properties of Tetrachlorethane, etc. 223 



Hence, therefore, tetrachlorethane is four times more toxic than chloro- 

 form, molecule for molecule, hut recovery from anaesthesia or paralysis is 

 more regular in the case of the former than in that of the latter. 



Trichlorethylene. 



Solutions. 



Times for abolition. 



Recovery. 





First Series. 







mins. 







9-5 



Delayed for some time, then 





fairly good. 



Chloroform, w/100 



17 -0 



Fairly good. 



Hence ratio cliloroform to trichloretliyleue = 1 : 1 ;8. 





Second Series. 





Trichlorethylene, h/200 



24 -5 



Good. 



Chloroform, «/100 



17 -0 



Fair. 



Hence ratio chloroform to trichlorethylene = 24 



•5/2 : 17 = 1 : 1 -5. 





Third Series. 





Trichlorethvlene, w/150 



25 '0 



Good. 



Chloroform^ «/100 



25 -0 



Fair. 



Fourth Series, repetition of Third, at higher temperatures. 



Trichlorethylene, n/150 



17-0 



Good. 



Chloroform, k/100 



17 -0 





The records obtained in the third series are illustrated in figs. 3 and 4. 

 Hence, trichlorethylene is l^o times more toxic than chloroform, molecule 

 for molecule, or 1-36 times, weight for weight. It will be observed on 



Fig. 3. 



