PHYSIOLOGICAL POSITION OF TOBACCO. 167 



by hand, or may be guided by means of a pantograph. The figure 

 having been thus traced on the roller, the latter is plunged into a bath 

 of nitric acid, which cuts into the metal at all points where the asphalt 

 coating has been displaced. Finally, the asphalt is washed off with 

 essence of turpentine. 



But the figures are usually produced on the roller by means of the 

 molette. This is a small cylinder of steel, into the surface of which 

 the engraver first cuts the design. This cylinder then gives to another 

 an impress in relief; and, finally, from this latter a concave impress is 

 taken on the large copper roller of the printing-press. It is plain that 

 as many rollers will be required as there are colors to print ; and, ow- 

 ing to the difficulty of preventing the colors running into one another, 

 not more than four are commonly employed black, red, rose, and 

 violet ; or black, brown, red, and cashew. In twelve hours, 100 to 

 120 pieces, of 50 yards each, may be printed in one color, though not 

 more than 60 to 80 could be printed in four. 



The capital employed in the manufacture of printed goods of mixed 

 fibre is enormous, and yields a large return. This manufacture gives 

 also good remuneration to the operatives, and there is every reason 

 why it should be as zealously fostered as the manufacture and employ- 

 ment of muslins and calicoes are to be discouraged, as tending to 

 draw off to America all the wealth of Europe. 



-+*+- 



THE PHYSIOLOGICAL POSITION OF TOBACCO. 



Br W. E. A. AXON, M. E. S. L. 



IN" speaking of the physiological position of tobacco, we have to deal 

 with the action of the essential principles of that plant upon the 

 human system. The peculiar effects of tobacco are due to the action 

 of the essential oil of tobacco in the case of chewing and snuffing, 

 and to that combined with the empyreumatic oil in smoking. Nico- 

 tine, as this essential principle is called, is so deadly an alkaloid, that 

 the amount of it contained in one cigar, if extracted and administered 

 in a pure state, would suffice to kill two men. According to the experi- 

 ments of "Vohl and Eulenberg, the nicotine is decomposed, in the pro- 

 cess of smoking, into pyridine, picoline, and other poisonous alkaloids, 

 which can also be obtained in varying quantities by the destructive dis- 

 tillation of other vegetable substances. 



Nicotine, as for convenience we may continue to call the poisonous 

 principles of tobacco, can enter the body through various channels by 

 the stomach, by the lungs, by subcutaneous injection, and by the skin 

 itself. But, in whatever manner it enters the human system, its effects 

 are, in the main, uniform. 



The most immediately noticeable symptom following smoking is the 



