354 



Lee 



amount of air passing through B, it is possible to obtain a condition in 

 which the smoke is comparable in amount to that which is inhaled by 

 man : this condition is gauged by the rate at which the cigarette or 

 cigar burns. 



The effect of such smoking on a cat is shown in fig. 7. 



In this cat the blood-pressure rose 20 or 30 mm. Hg during the 

 first five minutes of smoking, and then began to fall, in spite of the fact 

 that the smoking was still going on. This condition may be regarded as 

 typical, and bears a close analogy to that which occurs in man. Occasion- 

 ally, when the blood-pressure began to fall, the animal showed convulsive 

 movements. The ultimate effect, after smoking two or three cigarettes, was 

 a considerable fall in blood-pressure. 



In one experiment, during the inhalation, a quantity of moisture from 



Inteatine. 



Fig. 8. — Cat Brain destroyed by pithing. Artificial respiration. Intestinal volume. 



Blood-pressure. 



Shows the effect of accidental inhalation of tobacco ]aic«. Time, 30 seconds. 



the cigar condensed on the glass tube, just in front of the tracheal tube. 

 This during one inspiration was blown into the trachea, and produced an 

 immediate rise of blood-pressure with marked constriction of the blood- 

 vessels. This is shown in fig. 8, in which the upper tracing represents the 

 intestinal volume, the lower the blood-pressure. It is just such sudden 

 increases of blood-pressure as these which stretch and rupture the elastic 

 fibres in the vessels, as described later. The experiment illustrates the 

 possible dangers attendant on the u.se of foul pipes and the latter end of a 

 cigar, although they may be exaggerated in this instance, since the fluid 

 passed directly into the trachea and not into the mouth, as would be the 

 case in man. 



The ultimate effect on blood-pressure is shown in fig. 9. It this case a 

 rabbit was used, anaesthetised with urethane. The tracing A shows the 

 height of the blood-pressure before the smoking commenced, while B 



