B.— CHEMISTRY 59 



the side chain upon the bactericidal properties of substituted resorcinols. 

 Johnson and Lane (1921) showed that the phenol coefficients of 4-w- 

 alkylresorcinols rose steadily in the series methyl, ethyl, propyl and 

 butyl, whilst Dohme, Cox and Miller (1926), continuing the series, found 

 a maximum at 4-«-hexylresorcinol, which had a phenol coefficient of 50, 

 the values for w-amyl- and n-heptyl-resorcinol being 33 and 30 respec- 

 tively. They also showed that the antiseptic value of the w-alkylresor- 

 cinols were greater than those of branched chain alkylresorcinols having 

 the same number of carbon atoms. 



Coulthard, Marshall and Pyman (1930) studied the variation of phenol 

 coefficient with increase in the n-alkyl-side chain in the 4-n-alkylphenols, 

 4-«-alkylguaiacols and in four series of n-alkyl-cresols, of which the 

 4-n-alkyl-OT-cresols are the most important. In all cases the maximum 

 effect was shown where the side chain was a n-amyl group. The alkyl- 

 cresols had higher phenol coefficients than alkylphenols containing the 

 same alkyl group, whilst the alkylguaiacols were far less active. 



Phenol Coefficients. 

 /)-n-Alkylphenols. 4-«-Alkyl-m-cresols. 4-«-Alkylguaiacols. 

 R R 



/\Me 



OH OH 



R-CH3 2-5 — 



C2H5 75 12-5 



n-C3H7 20 34 



n-C4H9 70 100 



w-CgHn 104 280 



n-CgHij 90 275 



n-C^Hjs 20 30 — 



4-w-Amyl-OT-cresol, which had a phenol coefficient of 280 against 

 B. typhosus, proved to be highly bactericidal when tested against many 

 other species of bacteria. This is shown in the following table : 



Concentration lethal in Ritleal 



7I mins. not in 5 mins. Walker. 



Test Organism (i) Amyl-m-cresol. (2) Phenol. Coefficient. 



B. coli . . . 1-16,250 1-80 200 



Staphylococcus aureus . 1-20,000 1-90 220 



Streptococcus fcecalis . 1-15,000 1-75 200 



Pharmacological experiments having shown that it had less than one- 

 half of the toxicity of hexylresorcinol, and that it was non-toxic in 

 medicinal doses, further work was carried out to determine its suitability 

 for use in a mouth wash. In order to test its efficiency in this respect, 

 different dilutions of amyl-w-cresol, compared with plain water as a 

 control, were added to 5 c.c. of a mouth washing. The mixture was 



