sy a SD, oe 
. pia 4” 
62 REPORT OF SCHIMMEL 8 Co. OCTOBER 1914 / APRIL 1915, 
used as an indicator of vanillin; on evaporating with vanillin and sulphuric acid, it 
gives a red coloration, which gradually passes into violet, and evolves a camphor-. 
like odour. _ | 
Nothing is said in the treatise as to whether similar colour reactions are to be 
noticed with bodies allied to vanillin. Generally speaking, such reactions fail as soon. 
as the substances in question are not pure but mixed with other bodies that frequently 
influence the reaction. 
Haussler further carried out reactions of vanillin with albumen (from eggs and 
blood), fibrin, casein, Witte’s peptone, rennet and pure gelatine; he likewise determined 
what colour reaction urea gives with vanillin. It resulted that by means of the vanillin 
reactions albuminous substances can be detected with certainty, on the one hand 
among their resolution products, on the other, most likely also among enzymes. 
Proteins give with vanillin and hydrochloric or sulphuric acid a reddish blue-violet 
coloration, which proteids do not. The decomposition products of protein and allied 
compounds show the characteristic, sulphur-yellow colour, owing to their amide and 
jmide groups, whereas in combinations obtained with the aid of alkalis or through 
decay, such as indole and scatole, a red colour results. Urea behaves in a similar way. 
In order to find out the constitution of the coloured compounds, vanillin was . 
condensed with sulphanilic acid, when potassium 1-hydroxy-2-methoxy-4-benzylidene- 
1-aniline-4-sulphonate, a crystalline powder of orange-red colour, is formed. 
