4 THE COMPOSITION OF EXPIRED AIR, 



cies on the part of those continually bieatliing such air, and laid iluwii the rule, 

 which has been accepted and taught by sanitaiians for thiity-Hve years, that the 

 j)r(>portion of carbonic acid in the atmospheie of inhabited places aft'oi-ds a safe 

 indication as to the amount of the other impurities resulting from respiration and 

 other exhalations from the bodies of the occupants. 



Hammond, in 1863, (10), reported experiments in which he sought to remove 

 the carbonic acid and moistui-e, and to supply fresh air as fast as it is needed to 

 take the place of the carbonic acid removed, thus leaving the ''organic matter" to 

 accumulate in the vessel. For this purpose he confined a mouse in a large jar, in 

 which were several sponges saturated with baryta-water, by which the cai'bonic 

 acid was removed as fast as foimed. Fresh air was supplied as fast as required by 

 means of a tube communicating with the bell jar and closed by water in the bend 

 of the tube, which acted as a valve. As the air in the bell glass was rarefied by 

 respiration and absoi'ption of the carbonic acid, fresh air fiowed in from without, 

 while the arrangement of the tube prevented the air of the bell glass from passing 

 out. The watery vapor exhaled by the animal was absorbed by two or three 

 small pieces of chloride of calcium. The mouse died in forty minutes. Tlie 

 obseivation was repeated many times, and death ensued invariably in less 

 than an hour. On causing the vitiated air to pass through a solution of 

 permanganate of potash the presence of organic matters in large (juautity was 

 demonstrated. 



Ransome, in 1870, (11), reported a series of very interesting investigations 

 upon " Organic Matter of Human Bi-eath in Health and Disease." By condensing 

 the aqueous vapor of the liuiiiaii bicatli and analyzing it by the Wauklyu and 

 Cha[)man method, he found that "in ordinary respiration about 0.2 g. of organic 

 matter is given off from a healthy man's lungs in 24 hours," while in the air 

 expired by persons affected with certain diseases, he found great variations in the 

 amount of organic matter, the amount being greatest in a case of phthisis compli- 

 cated with Bright's disease. 



Smith (12) employed a lead chamber in his investigations upon the question 

 whether human lungs give off any poisonous agent other than carbonic acid, lie 

 found the pulse to fall fiom 73 to 57 beats per minute, and the number of I'espirations 

 to rise from 15.5 to 24, as the carbonic acid in the atmosphere inci'eased fiom .04 

 to 1.73 pel- cent, during four hours. When the proportion of carbonic acid lose to 

 3 per cent, there appeared great weakness of the circulation with slowing of the 

 heart's action, and great difiiculty in respiration. He believed that these results 

 should be attributed to other conditions rather than to the e.xcess of carbonic acid, 

 because he found later that it was only when lamps became dim in an atmosphere 



