260 A MANUAL OF BACTERIOLOGY 



four hours in a mixture consisting of 1 per cent, formic 

 acid and 1 in 5000 mercuric chloride. After this treatment 

 the skins are soaked in a strong brine solution. The 

 writer, however, has found that for horse-hair the solution, 

 to be efficient, must be two or three times stronger 

 than this. As regards horse-hair, Webb and Duncan 1 

 carried out a number of experiments on its disinfection, 

 from which it would seem that, leaving out of considera- 

 tion 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 obtained only with 

 minute care in the construction and regulation of the 

 apparatus. Legge concludes that to secure certain de- 

 struction 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 subjecting 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. 2 



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

 wool, but the fibres are materially damaged by the process. 3 



A number of cases of anthrax, resulting in many deaths, 

 have been reported in various parts of the United States 

 from tanneries dealing with hides imported from China. 



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

 p. 278. 



2 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. 



3 See Eighth Rep., Anthrax Investigation Board. 



