PHENOLOID SUBSTANCES 



771 



germicidal power are now to be obtained. Such are 

 cyllin, McDongalPs M.O.H. fluid, izal, kerol, etc. The 

 active agents appear to be oxidised hydrocarbons without 

 phenol and cresol, in emulsion in glue, soaps, oils, etc., 

 and they are comparatively non-toxic. The active 

 principle of cyllin is an oxidised hydrocarbon, having a 

 diphenyl nucleus in place of the single phenyl present in 

 carbolic acid ; it is insoluble in water, hence for the pur- 

 pose of even distribution in water it is emulsified with a 

 neutral hydrocarbon oil. The finished product contains 

 50 per cent, of the active principle, and is free from 

 carbolic acid and its homologues. The active principle 

 of kerol consists of oxidised hydrocarbons with a diphenyl 

 nucleus, and it contains no phenol or cresol. The germi- 

 cidal efficiency, expressed as the carbolic -acid coefficient 

 (p. 776), of a number of substances is given in the table 

 on p. 770. 



Some of the anilin dyes have been claimed to be power- 

 fully antiseptic. Of these the best known are Brilliant 

 Green, Malachite Green, Crystal Violet and Flavine. 

 Browning and co-workers l state that these have the 

 following germicidal potency on the M . pyogenes aureus 

 and B. coli : 



1 Brit, Med. Journ., 1917, vol. i,p. 73, 



492 



