1911.] Ventilation of the Lung during Chloroform Narcosis. 363 



Example III— In the following experiment the animal was anaesthetised 

 under a bell-jar with chloroform, the necessary operative procedures carried 

 out, and then placed in the plethysmograph and allowed to recover until 

 all the reflexes were well marked and voluntary movements returned. 

 When the respiration was steady and equable, 2'5 per cent, of chloroform 

 was given, and, as the tracing (fig. 9) shows, there is no very marked 

 effect on the respiration leading to a danger-point. After the third minute 



Fig. 9. 



Depth of respiration, 1 division = 22"22 c.c. ; time intervals, 30 sees. ; 4, 2'5 per cent, of 

 chloroform. 



the percentage of chloroform was gradually reduced to 1 per cent., and 

 the lung ventilation remained practically the same. After the 10th minute 

 the chloroform was stopped, the animal allowed to recover until the reflexes 

 returned seven minutes later. A high percentage of chloroform (5 per cent.) 

 was now given, and the animal died in nine minutes. A slowing of the 

 respiration occurred at first, but no cessation. Such a percentage administered 

 to an animal not previously anaesthetised with chloroform would almost 



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Fig. 10. 



Depth of respiration, 1 division = 22"22 c.c. ; time intervals, 30 sees. Upper tracing 

 represents the first 2 niins. of 5 per cent, chloroform, the lower the 4th to 6th mins. 

 VOL. LXXXIV. — B. 2 E 



