352 Lee 



on the moderate smoker. If the moderate smoker smokes to excess, he 

 assumes the position of a novice, and a climax would be reached in which 

 the nicotine and other constituents of -tobacco smoke would accumulate 

 in the blood to an extent which would paralyse the nerve cells, and 

 produce the sudden fall of blood - pressure characteristic of collapse. 

 Why the moderate smoker is able to withstand the action of smoking 

 so much better than the novice, is a question with which I propose to 

 deal elsewhere. 



The third group — the excessive smokers — an example of which is shown 

 in protocol 8, is merely an exaggeration of group 2. The pressure rises 

 only 2 mm. or 4 mm. Hg, and such as it is, is maintained in the same 

 way as in group 2 until smoking ceases, when it returns again to the 

 normal. The pulse in these cases is not affected. 



VI. The Effect of Smoking on Animals. 



(a) Immediate Effects. — The effect of inhalation of tobacco smoke on 

 ansesthetised animals was determined by connecting a tracheal tube, which 

 has in it a suitable lateral opening, capable of being regulated in size, with 

 a lighted cigarette. The animal will then inhale the smoke with a variable 

 admixture of air according to the size of the aperture in the lateral tube : 

 the inhalation will be on much the same principle as when man inhales. 

 The objection to this mode of procedure is the effect of the smoke on 

 respiration : the animal ceases to breathe for a time, or the respiration 

 becomes feeble and irregular, and this results in a variety of secondary 

 circulatx)ry disturbances from the spasmodic breathing, or from partial 

 asphyxia, so that it is almost impossible to say which circulatory effects are 

 due directly to smoking and which are due to irritation of the respiratory 

 tracts. 



To obviate this difficulty an alternative mode of administering the 

 smoke was adopted. A normal animal was first killed by the destruction 

 of the brain and medulla oblongata by pithing, without the ase of any 

 anaesthetic, artificial respiration being started. In the course of the air 

 tube was inserted a special apparatus, devised for these experiments, which 

 is shown in fig. 6. The current of air was divided by a Y-tube, the one 

 limb carrying the air directly to the trachea tube, the other through a 

 chamber in which, by allowing a regulated quantity of air to pass through 

 it, tobacco in the form of a cigar or cigarette could be burnt at any 

 required rate. The two streams of air were brought together again 

 by a second Y-tube, the single limb of which was connected to the 

 trachea tube. 



A glance at tig. 6 shows that when a lighted cigarette or cigar is placed 

 in the tube A, if the tube B is closed during the down-thrust of the pump 

 all the air will pass through the tube A and through the cigarette or 

 cigar, and thus the animal will receive the smoke. By regulating the 



