METHYLATION. 787 



was observed. In perfusion experiments with dog livers, EMBDEN and 

 SCHMITZ 1 have shown the formation of phenylalanine, tyrosine and other 

 amino-acids, as has already been mentioned (pages 530 and 775) by 

 synthesis from the ammonium salts of the corresponding keto-acids and 

 also in part from the oxy-acids. 



Methylation also often occurs, and as an example we will mention that 

 His has shown that pyridine, CsH 5 N, is transformed in dogs into methyl- 

 pyridine, and then passes into the urine as methylpyridylammonium 

 hydroxide. Pyridine behaves similarly in hens (HosniAi), pigs and goats, 

 (TOTANI and HOSHIAT) while according to ABDERHALDEN 2 and collabora- 

 tors, in rabbits it passes unchanged into the urine. Further examples 

 of methylation, although not aromatic substances, are the conversion 

 of guanidine acetic acid into creatine (JAFFE) and the observation of 

 TAKEDA 3 of the appearance of aminobutyrobetaine in the urine of dogs 

 with phosphorus poisoning. 



Several alkaloids, such as quinine, morphine, and strychnine, may pass into 

 the urine. After the ingestion of turpentine, balsam of copaiba, and resins, these 

 may appear in the urine as resin acids. Different kinds of coloring-matters, such 

 as alizarin, crysophanic acid, after rhubarb or senna, and the coloring-matter of 

 the blueberry, etc., may also pass into the urine. After rhubarb, senna, or santonin 

 the urine assumes a yellow or greenish-yellow color, which is transformed into 

 a beautiful red by the addition of alkali. Phenol produces, as above mentioned, 

 a dark-brown or dark-green color which depends mainly on the decomposition 

 products of hydroquinone and humin substances. After naphthalene the urine 

 has a dark color, and several other medicinal agents produce a special coloration. 

 Thus after antipyrine it becomes yellow or blood-red. After balsam of copaiba 

 the urine becomes, when strongly acidified with hydrochloric acid, gradually 

 rose- and purple-red. After naphthalene or naphthol the urine gives with con- 

 centrated sulphuric acid (1 cc. of concentrated acid and a few drops of urine) 

 a beautiful emerald-green color, which is probably due to naphthol-glucuronic 

 acid. Odoriferous bodies also pass into the urine. After asparagus the urine 

 acquires a digusting odor which is probably due to methylmercaptan. After 

 turpentine the urine may have a peculiar odor similar to that of violets. 



VI. PATHOLOGICAL CONSTITUENTS OF URINE. 



Proteid. The appearance of slight traces of proteid in normal urine 

 has been observed by many investigators, such as POSNER PL6sz, v. 

 NOORDEN, LEUBE, and others. According to K. MORNER* proteid 

 regularly occurs as a normal urinary constituent to the extent of 22-78 



1 Knoop, Zeitschr. f. physiol. Chem., 67; Embden and Schmitz, Bioch. Zeitschr., 29 

 and 38. 



2 His, Arch. f. exp. Path. u. Pharm., 22; Cohn, Zeitschr. f. physiol. Chem., 18; 

 Hoshiai, ibid., 62; with Totani, ibid., 68; Abderhalden and collaborators, ibid., 59 

 and 62. 



3 Jaffe, Zeitschr. f. physiol. Chem., 48; Takeda, Pfluger's Arch., 133. 

 4 Skand. Arch. f. Physiol., 6 (literature). 



