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themselves, are developed in certain constitutions, upon a 

 proper exciting agent or irritation being applied. Under 

 the microscope, there is no difference between the tubercle 

 or bleb, caused by rubbing croton oil upon the skin, and 

 that produced in the lungs, and which leads to consumption. 

 Like gout, phthisis is either hereditary or may be acquired, 

 and the disease is said by Dr. Maxx scarcely to occur at 

 all in Egypt ; and it is also stated that in countries where 

 aqueous exhalations cause intermittent fevers, phthisis is 

 little known. Dr. Guy, professor of forensic medicine in 

 King's College Hospital, in the Commissioners' Report 

 gives ample proof of the injurious effects of deficient ven- 

 tilation. He states the proportion of consumptive cases 

 in the three classes of persons, viz: — gentlemen, (including 

 professional), tradesmen, and artisans, as 16.28 and 30 per 

 cent ; so that the tradesmen of the metropolis are nearly 

 twice as liable to consumption as the gentry ; and the 

 greater mortality, Dr. Guy thinks, is mainly attributable 

 to their confinement during so many hours of every day 

 in ill-ventilated shops, and, especially, when dust is inhaled 

 and gas-burners are used. He further states, that about 

 36,000 persons in England and Wales die of true pulmo- 

 nary consumption, and that by proper sanitary measures, 

 not less than 5,000 might be saved. It appears again from 

 the researches of Dr. Carpenter, that at each inspiration 

 20 cubic inches of air is taken in, and, therefore, 266^ cubic 

 feet in 24 hours. But Dr. Guy adduces some cases where 

 104 men, working in a room with less than 500 cubic feet of 

 air to breathe in, were affected by spitting of blood, catarrh, 

 and other lung diseases, to the amount of 42 per cent. ; 

 while 115 men, having from 500 to 600 cubic feet, were 

 affected to 27 per cent, with the same complaints ; while 

 101 men, with more than 600 cubic feet, were affected only 

 to the amount of 23 per cent. 



