90 Journal of Agricultural Research voi. iv. no. i 



others working with naturally infected hides, it is evident that the spores 

 upon such hides frequently possess very high vitality and virulence. 

 Therefore it seems that the only safe rule to follow is to use only such 

 disinfectants and such methods of disinfection as have been found 

 efficient against spores of maximum vitality and virulence. 



SUMMARY AND CONCLUSIONS 



(i) The Seymour-Jones method. — The strength of disinfectant orig- 

 inally recommended by Seymour-Jones (mercuric chlorid, i to 5,000, plus 

 I per cent of formic acid) was not found to be efficient, even without 

 neutralization of the disinfectant. A stronger dilution, i to 2,500, plus 

 I per cent of formic acid, was found to be efficient where no neutralization 

 was attempted. The latter strength was not sufficient, however, to 

 prevent fatal infection of guinea pigs by disinfected material when the 

 disinfectant was neutralized by a i per cent sodium-sulphid solution 

 three or four days after the completion of the process of disinfection. 

 No infection was caused by the inoculation of material which had been 

 kept a week or more after disinfection. It seems, therefore, that the 

 Seymour-Jones method might be employed with dilutions of mercuric 

 chlorid, i to 2,500, plus i per cent of formic acid, provided the treated 

 hides are not to be subjected within a week or two to the action of any 

 substance which will neutralize the disinfectant. This would be the 

 case, for instance, if hides were disinfected at foreign ports before ship- 

 ment to this country. 



(2) The Schattenfroh method. — Hydrochloric acid and sodium 

 chlorid in the proportions of 2 per cent of the acid and 10 per cent of the 

 salt and with 48 hours' exposure have proved efficient in every instance. 

 Consequently from the bacteriological standpoint the Schattenfroh 

 method seems to be entirely satisfactory. This conclusion is supported 

 not only by this work but by the exhaustive researches of Gegenbauer 

 and Reichel (3) and Hilgermann and Marmann (4). The recently pub- 

 lished work of Sevi^ik(i5) is not so favorable to the Schattenfroh method 

 as that of the investigators previously mentioned. He finds that com- 

 plete disinfection can be accomplished when the hides worked with are 

 thin. But when the hides are thick and heavily infected, he was able, 

 after very thorough neutraUzation, to extract from pieces of the treated 

 hides anthrax spores which were virulent for mice, and in some instances 

 for guinea pigs, even after exposure to a solution of 2 per cent of 

 hydrochloric acid plus 10 per cent of sodium chlorid for 7 days. 



Although in view of the above-mentioned results the Schattenfroh 

 method can not be regarded as perfect, it nevertheless seems to be far 

 superior to other methods and well worth a trial as a standard method 

 for the disinfection of hides. 



(3) Effect of disinfection upon hides as regards tanning. — 

 Mr. F. P. Veitch, Chemist in Charge of the Leather and Paper Laboratory 



