LEUOOMAINS OF EXPIRED AIR. 461 



mercuric oxid it assumes an alkaline reaction, and the filtrate on 

 heating yields metallic mercury. With silver oxid it forms pearly 

 lanceolate plates having the composition C^HjNjO^.Ag. It does 

 not give the alkaloidal reactions. 



UNDETERMINED LEUCOMAINS. 

 Leucomajms of Expired Air. 



It was shown at quite an early period that exhalations from ani- 

 mals contain, besides an increased amount of carbonic acid, some 

 organic matter, the nature of which, on account of the exceedingly 

 minute quantity in which it occurs, has never been satisfactonly 

 determined. Eansome, in 1870, estimated the organic matter in 

 expired air by permanganate of potash to be about 0.2 g. per day. 

 Later Uffelmann showed that the amount of the organic matter in 

 occupied closed rooms increased in almost the same ratio as carbonic 

 acid. Herrmanns, however, denied the existence of organic sub- 

 stances in the expired air. Nevertheless, various observers did not 

 hesitate to ascribe to it the ill effects consequent upon breathing im- 

 pure air, while at the same time the carbonic acid formed during 

 respiration was considered as either entirely inert or as insignificant 

 in its action. Thus, respired air from which moisture and carbonic 

 acid have been removed, but which still contains the organic vapors, 

 was found by some to be highly poisonous. On the other hand, if the 

 respired air is drawn through a red-hot tube, to destroy the organic 

 matter, the air thus purified is capable of sustaining life even in 

 presence of a large percentage of carbonic acid. While it cannot 

 be, therefore, doubted that the organic matter of expired air plays a 

 most important part in producing the well known noxious effects 

 resulting from breathing confined and vitiated air, nevertheless it 

 would seem from experiments made by Angus Smith that the increase 

 of even such small quantities of carbonic acid in the air as from 0.04, 

 the normal amount present, t« 0.1 per cent., is capable of producing 

 systemic disturbances characterized by a decrease in the pulse rate 

 and an increase in the rate of respiration. 



Smith was consequently of the opinion that the constant lowering 

 of the pulse in impure air, occasioned by the presence of carbonic 

 acid, must have a depressing effect on the vitality. Whatever ill 

 effects the carbonic acid may produce of itself, it remained quite cer- 

 tain that this gas was not the most potent and most injurious con- 

 stituent of respired air ; and the investigations of Hammond, Nowak, 

 Seegen, and others pointed to the organic matter as the direct and 

 immediate agent which produces those symptoms of sickness and 

 nausea experienced in badly ventilated closed rooms. 



Of special importance to the sanitarian and physician is the work 

 on the nature and action of the poisonous principle of expired air 



