1915] Edgar G. Miller, Jr. 225 



agents (hydrogen peroxid, sodium peroxid, nitric acld, potassium 

 nitrate, manganese dioxid, potassium chlorate, potassium di-chro- 

 mate, potassium permanganate) destroy the color or inhibit its 

 formation. Furthermore, the color sometimes fades when the 

 colored sol. exposed to the air is allowed to stand. 



Many organic substances reduce acidified sol. of ammonium 

 molybdate. Sulfuric acid gives far better results than hydrochloric 

 acid; phosphoric and nitric acids should not be used. To deter- 

 mine the influence of the conc. of sulfuric acid upon the intensity 

 of the reduction three reagents were prepared. Reagent A con- 

 sisted of 30 gm. of ammonium molybdate, and 25 cc. of conc. sul- 

 furic acid in i 1. of dist. water. Reagent B contained the same 

 amount of molybdate, but 50 cc. of the acid per 1. Reagent C con- 

 tained 100 cc. of the acid per 1. The sol. to be tested were heated 

 in a water-bath for f rom 5 to 30 min. It was found that Reagent 

 A yielded the most intense reductions, Reagent B gave weaker colors, 

 while Reagent C gave negative results in most cases. The greater 

 the conc. of sulfuric acid, the less sensitive the reagent. 



Many Compounds gave strikingly beautiful reactions. These 

 are fructose and the carbohydrates that yield it by hydrolysis (su- 

 crose, raffinose, inulin), rhamnose, arabinose, xylose, maitose, 

 starch, glycogen, dextrin, agar-agar, amygdalin, salicin, esculin; 

 the gums — benzoin, tragacanth, gambir, asafetida, guaiac, myrrh, 

 kino and acacia; mucic acid, formaldehyde, trioxymethylene, ace- 

 taldehyde, acetaldehyde-ammonia, reduced oxalic acid, erythro!, 

 resorcinol, tricresol, hydroquinon, orcinol, tartaric acid, malic acid, 

 tannic acid, amidol; Phenylhydrazin, (cold), /7-phenylene-diamin, 

 benzidin and hydroxylamin hydrochlorids ; hydrazin sulfate, casein- 

 ogen, osseomucoid and thiourea. Less intense reduction was observed 

 with glucose, arbutin, mannite, aceto-acetic ester, chloral, benzal- 

 dehyd, p-nitrobenzaldehyd, di-methyl aminobenzaldehyd, cinnamic 

 aldehyd, salicylaldehyd, Cumarin, acetone, /?-amidoacetophenon, 

 methyl alcohol, ethyl alcohol, glycerol, phenol, m- and />-cresols, 

 thymol, <2-naphthol, phloroglucinol ; oxalic, citric, gallic, lactic, and 

 uric acids; caffein, salicylic acid, asparagin, leucin, edestin, egg 

 albumen, fibrin, collagen, gelatin, proteoses, serum protein, mucoid, 

 ovalbumin, Creatinin zinc chlorid, nitrobenzol, lecithin, choles- 



