336 Lee 



being produced during the destruction of some of the nicotine, the latter 

 from the combustion of the fibres in the tobacco. 



Hydrocyanic acid, 008 g. 



Ammonia, 036 g. 



Carbon tnonoxide, 410 c.c. 



These amounts vary with many factors. Thus the length of the tube 

 through which the smoke passes — by allowing the deposition of the solid 

 matter and the condensation of vapour — materially affects the composition 

 of the smoke J the principle of this is illustrated in the "churchwarden" 

 pipe. Again, the quality of the tobacco varies within the widest limits; 

 evidence will be produced on this point later. For the purposes of experi- 

 ment some standard tobacco must be adopted and retained throughout. 

 The tobacco which was chosen for these experiments was of two varieties : 

 — 1. A sample of Virginian tobacco from the " untreated " leaf, prepared 

 for smoking in cigarette form; this was kindly provided by Mr Player. 

 2. A very strong variety of Manilla cigar. 



In order to determine the amount of nicotine or blood-pressure-raising 

 substances present in these two tobaccos, equal weights were taken and 

 macerated, each in the same quantity of normal saline solution. The 

 solutions were then filtered, and the amount of nicotine or blood-pressure- 

 raising substances estimated physiologically by their power of raising blood- 

 pressure. For this purpose cats were pithed or anaesthetised with urethane, 

 and the blood-pressure recorded by a mercurial manometer. The following 

 figures show the result of these experiments : — 



One gram of cigarette tobacco and 1 gram of Manilla tobacco were 

 macerated each in 100 c.c. of saline and allowed to stand for two days. 

 The infusion resulting was filtered, and a fluid suitable for intravenous 

 injection was obtained. 



Equal quantities of the two solutions were injected into the jugular 

 vein of a pithed cat, and the relative rise of blood-pressure when the amount 

 injected was not excessive was as follows : — 



Manilla tobacco, 25*6 mm. Hg. 

 Cigarette „ 42-4 



A solution of the crude leaf from which this sample of cigarette 

 tobacco was prepared (1 gram to 100 c.c.) produced a rise of 56 mm. Hg. 

 The last result shows that during the course of preparation a considerable 

 quantity of nicotine or pressor substance is destroyed. This is not surpris- 

 ing, as it is well known, that fermentation reduces the amount of nicotine 

 in tobacco. From these experiments it is obvious that the Manilla tobacco 

 contains much less nicotine than the Virginian. It does not, however, 

 necessarily follow that because one tobacco contains less nicotine than 

 another, it will yield less nicotine when it is smoked. For this reason a 

 second series of experiments was conducted by drawing the fumes from the 



