272 ACCIDENTAL IMPURITIES IN THE AIR. 



(c.) Reducing gases. (1.) H 2 S (sulphuretted hydrogen) rapidly robs blood- 

 corpuscles of O : S and HgO being formed, and death occurs rapidly before the 

 gas can decompose the haemoglobin (Hoppe-Seyler). 



(2.) PHa Phosphuretted hydrogen is oxidised in the blood to form phosphoric 

 acid and water with decomposition of the haemoglobin (Dybkowski, KoschlakofF, 

 and Popoff). 



(3.) AsH 3 , arseniuretted hydrogen and SbH 3 , antimoniuretted hydrogen, act 

 like PHs, but in addition, the haemoglobin passes out of the stroma and appears in 

 the urine. 



(4.) C 2 N 2 , cyanogen absorbs 0, and decomposes the blood (Rosenthal and 

 Laschke witsch ) . 



HI. Irrespirable gases, i.e., gases which, on entering the larynx, cause reflex 

 spasm of the glottis. When introduced into the trachea they cause inflammation 

 and death. Under this category come hydrochloric, hydrofluoric, sulphurous, 

 nitrous, and nitric acids, ammonia, chlorine, fluorine, and ozone. 



136. Accidental Impurities of the Air. 



Bust Particles. Amongst these are dust particles which occur in enormous 

 amount suspended in the air, and thereby act injuriously upon the respiratory 

 organs. The ciliated epithelium of the respiratory passages eliminates a large 

 number of them. Some of them, however, reach the air-vesicles of the lung, 

 where they penetrate the epithelium, reach the interstitial lung-tissue and lym- 

 phatics and so pass with the lymph-stream into the bronchial glands. Particles 

 of coal or charcoal are found in the lungs of all elderly individuals, and blacken 

 the alveoli. In moderate amount these black particles do not seem to do any 

 harm in the tissues, but when there are large accumulations they give rise to lung 

 affections, which lead to disintegration of these organs. [In coal-miners, for 

 example, the lung-tissues along the track of the lymphatics and in the bronchial 

 glands are quite black, constituting " coal-miners' lung."] In many trades various 

 particles occur in the air; miners, grinders, stone-masons, file-makers, weavers, 

 spinners, tobacco manufacturers, millers, and bakers, suffer from lung affections 

 caused by the introduction of particles of various kinds inhaled during the time 

 they are at work. 



There seems no doubt that the seeds of some contagious diseases may be inhaled. 

 Diphtheritic bacteria become localised in the pharynx and in the larynx 

 glanders in the nose measles in the bronchi hay-monads in the nose. Many 

 seeds of disease pass into the mouth along with air, are swallowed, and undergo 

 development in the intestinal tract, as is probably the case in cholera and typhoid 

 fever. 



137. Ventilation of Rooms. 



Fresh air is as necessary for the healthy as for the sick. Every healthy person 

 ought to have a cubic space of 800 cubic feet, and every sick person 1000 cubic 

 feet of space. [The space allowed per individual varies greatly, but 1000 cubic 

 feet is a fair average. If the air in this space is to be kept sweet, so that the C0 2 

 does not exceed '06 p.c., 2000 cubic feet of air per hour must be supplied.] In 

 France only 42 cubic feet per head are allowed in barracks, 60 cubic feet in 

 hospitals. In Prussia in barracks 420-500 cubic feet are allowed for every 

 soldier, for hospital 600-720; in England 600 cubic feet per head. When there 

 is overcrowding in a room the amount of C0 2 increases, v. Pettenkofer found 

 the normal amount of CO 2 ( '04 to '05 per 1000) increased in comfortable rooms to 



