BUREAU OF ANIMAL, INDUSTRY. 147 



thought to be due to some form of toxin eliminated by the parasites. 

 A paper has been published giving in detail the observations made. 



An investigation into the cause of the souring of hams while in 

 the process of curing and smoking has been begun. This is a prob- 

 lem of considerable economic importance. 



In the bacteriological examination of specimens of sour beef, 

 Bacillus megatherium was found to be the cause of the condition. It 

 was also learned that this organism would sour beef at a wide range 

 of temperature, but not in the absence of oxygen. Propionic acid is 

 elaborated during the bacterial process. The organism and its prod- 

 ucts were found to be harmless to rabbits and guinea pigs, by feeding 

 as well as by injection. 



DIAGNOSIS OF DISEASES. 



EABIES. 



Specimens from 100 suspected cases of rabies were received and 

 submitted to laboratory examination. Fiftj^-six were positive, while 

 in two cases decomposition prevented a diagnosis. The number of 

 positive cases was nearly double that of the preceding year. The 

 positive cases were 47 dogs, 6 cats, 2 cattle, and 1 hog. A number 

 of persons, as well as dogs and other animals, were bitten by the 

 affected animals. In addition to the cases from the District of 

 Columbia, the material included cases from Maryland, Virginia, 

 West Virginia, Tennessee, and New Hampshire. The regulation 

 requiring the muzzling of dogs in the District of Columbia is in effect 

 from July 9 to October 23, or for 107 out of 365 days, or less than 

 one-third of the year. During the months of April, May, and June, 

 when dogs are not muzzled, 37 cases were examined for rabies, 17 

 being positive. The latter figure does not represent the full extent 

 of the infection, as a number of the cases are examined in other 

 laboratories and in some cases the animal is destroyed without 

 examination. 



TUBERCULOSIS. 



Specimen tissues taken from 1,422 cattle which had reacted to the 

 tuberculin test but hacl shown no visible lesions of tuberculosis on 

 autopsy were examined microscopically in the laboratory, and 290 

 of the samples were found to contain tubercle bacilli. The finding of 

 tubercle bacilli in skin lesions shows the importance of careful exami- 

 nation of the skin of reactor cattle on post-mortem examination. 



A number of nodular spleens from calves from 2 to 8 weeks old 

 were examined, and the lesions in several proved to be due to acid- 

 fast bacilli having the size and form of bovine tubercle bacilli. 



GLANDERS. 



Cooperative work in the control and eradication of glanders in 

 the various States was continued. The complement-fixation test 

 was applied to 159 samples of serum from animals suspected of being 

 affected with or exposed to glanders, and only one was found to give 

 a positive reaction. 



