EFFECT OF CHEMICAL AGENTS 337 



by permanent arrest of pulsation. In the experiment of 

 which a record is given (fig. 183), diluted chloroform vapour 

 was introduced into the chamber. This is observed at 



Fig. 183. — Effect of vapour of chloroform. Immediate excitatory 

 effect followed by depression and arrest. On blowing off the 

 anaesthetic, pulsations were revived after half an hour, repre- 

 sented by a gap in the record. 



first to have an excitatory effect in the first two pulsations. 

 The amplitude of the third pulsation became much reduced, 



Fig. 184. — Arrest of pulsation by vapour of carbon disulphide, 

 and revival after readmission of fresh air. Duration of 

 application indicated by the horizontal line under the 

 record. 



and an arrest ensued at the fourth pulsation after the appli- 

 cation of the anaesthetic. The vapour was then quickly 



