EFFECTS OF DIFFERENT GASES 93 



without the abolition of its excitabiUty. The effect of 

 the gas is very different when it contains impurities such 

 as sulphuretted hydrogen. I give a record (fig. 51) which 



Fig. 50. — E£fect of carbon disulphide. 



Fig. 51. — Effect of coal gas : note irregularity of response 

 after introduction. 



exhibits the depressing effect of coal gas, and the gradual 

 restoration of normal excitability on admission of fresh air. 



Chloroform 



The vapour of chloroform acts as a very strong narcotic. 

 In the record here given (fig. 52) the response became very 



