28 PHYSIOLOGICAL CHEMISTRY 



with the Fehling's test do not interfere with the Nylander test. It 

 is claimed by Bechold that the bismuth reduction tests give a negative 

 reaction with solutions containing sugar when mercuric chloride or 

 chloroform is present. Other observers 1 have failed to verify the 

 inhibitory action of mercuric chloride and have shown that the in- 

 hibitory influence of chloroform may be overcome by raising the tem- 

 perature of the urine to the boiling-point for a period of five minutes 

 previous to making the test. Urines rich in indican, urochrome, uroery- 

 thrin or hematoporphyrin, as well as urines excreted after the ingestion of 

 large amounts of certain medicinal substances, may give a darkening of 

 Nylander 's reagent similar to that of a true sugar reaction. It is a dis- 

 puted point whether the urine after the administration of urotropin 

 will reduce Nylander 's reagent. 2 Strausz 3 has recently shown that the 

 urine of diabetics to whom "lothion" (diiodohydroxypropane) has 

 been administered will give a negative Nylander-Almen reaction and 

 respond positively to the Fehling and polariscopic tests. " lothion" 

 also interferes with the Nylander-Almen test in vitro whereas KI and 

 I do not. 



According to Rustin and Otto, the addition of PtCl2 increases the 

 delicacy of Nylander-Almen reaction. They claim that this procedure 

 causes the sugar to be converted quantitatively. No quantitative 

 method has yet been devised, however, based upon this principle. 



Bohmansson 4 before testing the urine under examination treats 

 it (10 c.c.) with J^ volume of 25 per cent hydrochloric acid and about 

 J^ volume of boneblack. This mixture is shaken one minute, then 

 filtered and the neutralized filtrate tested by Nylander-Almen reaction. 

 Bohmansson claims that this procedure removes certain interfering 

 substances, in particular urochrome. 



A positive bismuth reduction test is probably due to the following 

 reactions: 



(a) Bi(OH) 2 NO 3 + KOH-Bi(OH) 3 + KN0 3 . 



(b) 2 Bi(OH) 3 -30 - Bi 2 + 3 H 2 0. 



(f ) Indigo Carmine Test. Place in a test tube 2 c.c. of water with an in- 

 digo sodium-carbonate tablet and one sodium carbonate tablet. 5 



Heat the tube gently until the indigo is dissolved. Add to the blue solution, 



1 Rehfuss and Hawk: Journal of Biological Chemistry; 7, 267, 1910; also Zeidlitz: 

 Upsala Lakareforen Fork., N. F., n, 1906. 



2 Abt: Archives of Pediatrics, 24, 275, 1907; also Weitbrecht: Schweiz. Wochschr., 47, 

 577, 1909. 



'Strausz: Munch, med. Wcoh,. 59 85, 1912. 



4 Bohmansson : Biochem. Zeit., 19, p. 281. 



5 These tablets may be obtained from Parke, Davis & Company. 



