vii KATABOLIC CONSTITUENTS OF UBINE 415 



blood, was demonstrated by Bickel (1901-3). By injecting 

 indifferent substances into the blood, he succeeded in raising its 

 molecular concentration to a much higher degree than is the case 

 in uraemia, without producing any of the symptoms exhibited by 

 uraemics. 



F. Marino- Zuco and K. Onorato (1904-5) have recently found 

 a characteristic poison in urine to which they have given the name 

 of biotoxin, because it is found not only in urine, but in all 

 the tissues and fluids of the human and animal body. They 

 extracted it from urine by concentrating 50 litres in a special 

 apparatus, at a temperature of 38 C., under aseptic conditions, 

 till a fluid of syrupy consistency was obtained. From this, after 

 repeated precipitation with alcohol and washing of the precipitate, 

 they obtained the pure toxin in the form of a light, white, 

 amorphous powder, devoid of odour, insoluble in alcohol, and giving 

 no protein reaction. 



This biotoxin is constantly present in the urine of man and 

 the higher vertebrates, both herbivora and carnivora, to an amount 

 of 0'3-0'5 per litre. It can, moreover, constantly be detected in 

 the kidneys and the blood ; and must therefore be a product of 

 metabolism, removed from the blood by the kidneys, and then 

 excreted. It has not yet been determined whether this elimina- 

 tion takes place solely in the kidneys, or whether other organs 

 share in it. In whatever way biotoxin is isolated it invariably 

 exhibits the same properties. Since on injection into the blood of 

 animals it induces morbid phenomena similar to those of uraemia, 

 while, on the other hand, there is less of it in nephritic than in 

 normal urine, Marino-Zuco and Onorato conjecture that the 

 accumulation of this poison in the blood, owing to functional 

 insufficiency of the kidneys, plays a considerable part in the genesis 

 of uraemia. 



BIBLIOGRAPHY 



The most important publications on the Constituents of Urine and their Origin 

 can be found in recent Text-books of Chemical Physiology and Monographs on 

 Urine, among which are : 



NEUBATJER and VOGEL. Anleitung zur qualitativen und quantitativen Analyse 



des Harns. 10th ed., enlarged and brought up to date by Dr. H. Huppert. 



Wiesbaden, 1898. 

 SALKOWSKI and LEUBE. Trattato dell' urina ad uso degli studenti e dei medici. 



Italian translation. Naples, 1886. 

 RE ALE and BOERI. Manuale di chimica clinica. Analisi delle urine e ricambio 



materiale. Naples, 1894. 

 L. ZOJA. Conferenze cliniche italiane dirette dal De-Giovanni, vol. i., 1897. 



(This monograph contains a full bibliography as regards the genesis of urinary 



pigments. ) 

 F. HOPPE-SEYLER and H. THIERFELDER. Handbuch der physiol. und patholog. 



chemischen Analyse. Berlin, 1903. 

 A. HEFFTER. Ergebn. d. Physiol. i. Part L, 1902. 

 M. JACOBY. Ergebn. d. Physiol. i. Part I., 1902. 



