DISINFECTION OF HORSEHAIR 315 



by Seymour Jones has been favourably reported on 1 ; 

 it consists in soaking the skins for twenty-four hours in a 

 mixture consisting of 1 per cent, formic acid and 1 in 

 5,000 mercuric chloride. After this treatment the skins 

 are soaked in a strong brine solution. The writer, how- 

 ever, found that for horsehair the solution, to be efficient, 

 must be two or three times stronger than this. As 

 regards horsehair, Webb and Duncan 2 carried out a 

 number of experiments on its disinfection, from which it 

 would seem that, leaving out of consideration white or 

 grey hair, which is liable to change colour, no injurious 

 effect is produced on hair by steam disinfection provided 

 the temperature does not exceed 218 F. ; but this is a 

 comparatively low temperature for efficient disinfection, 

 and success can then be attained only with minute care 

 in the construction and regulation of the apparatus. 

 Legge concludes that to secure certain destruction of all 

 anthrax spores in horsehair absolute reliance cannot be 

 placed on either steam disinfection (within the limits in 

 which it can be applied) or simple boiling. Adoption of 

 one or the other is a very material safeguard, but risk 

 must always be run by those who prepare the hair for 

 disinfection. Disinfection has been attempted by sub- 

 jecting the material to the action of certain phenoloid 

 disinfectants, but, from experiments by Hall and the 

 writer, a modified Seymour-Jones method or formalin or 

 bacterol seem to be the only efficient ones. 3 



Steam disinfection at 215-230 F. can be applied to 

 wool, but the fibres are materially damaged by the 

 process. 4 



1 Ponder, Report to the Worshipful Company of Leather sellers, 1911. 



2 Ann. Rep. of Chief Inspector of Factories, 1900, p. 472, and 1902, p. 278. 



3 In disinfection experiments with anthrax, agar should be used for the 

 subcultures, broth for some unexplained reason being inefficient. See 

 Hewlett and Hall, Journ. of Hygiene, xi, 1911, p. 473. 



4 See Eighth Hep. Anthrax Investigation Board. 



