CHEMISTRY OF THE LEUCOMAINES. 343 



stances formed in the body when there is an insufficient 

 air-supply are not eliminated in the exhaled air. 



Sewer-air, according to observations made by Odling, 

 contains a basic substance which is probably in composition 

 a compound ammonia. It contains, however, more carbon 

 than methylamine and less than ethylamine. 



It should be remarked that Jackson has (Dec. 1887) 

 announced the presence in expired air of quantities of car- 

 bon monoxide gas sufficient to produce the ill effects ordi- 

 narily attributed to the organic matter. The presence of 

 this poisonous gas must first be fully demonstrated before 

 it can be taken into account in the consideration of the 

 toxicity of air ; certainly, even if present, it cannot explain 

 the results obtained by the French investigators as stated 

 above. 



According to Ilosva, expired air contains nitrous acid. 

 This may possibly be derived from that which is constantly 

 being formed in the mouth, probably by the reduction of 

 nitrates (Miller). 



Leucomaines of the Urine. 



A number of basic substances have been isolated at 

 different times fi'om the urine, and on that account they 

 may be properly classed as leucomaines. Thus, Liebreich 

 (1869) found in the urine a base which apparently was an 

 oxidation-product of choline, and which has since been 

 regarded as identical with betaine. In 1866 DuPR:fi and 

 Bence Jones found, among other things in the urine, an 

 alkaloidal body which in sulphuric acid solution possessed 

 a blue fluorescence (see p. 347). Most of the members of 

 the uric acid group of leucomaines have been detected in 

 the urine and on account of their well-defined nature they 

 are described by themselves. In the urine and feces of 

 cystinuria Udranszky and Baumann discovered the well- 

 known ptomaines, cadaverine and putrescine. For isola- 

 tion, see pp. 207 and 208. 



In 1879, Thudichum announced the presence in the 

 urine of four new alkaloids, one of which, urotheobromine. 



