108 ANNUAL EEPORTS OP DEPARTMENT OP AGEICULTURE. 



that this animal possessed a high degree of immunity to botulinus 

 infection. 



The outcome of the year's observations tends to strengthen the 

 theory that Bacillus botulinus is the factor to be reckoned with in 

 many cases of forage poisoning; however, definite proof was not 

 obtained. 



MAMMITIS. 



An effort has been made to study the effects of autogenic bac- 

 terins upon cases of mannnitis or garget. Bacteriological investiga- 

 tions have shown that many cases arise in which no streptococci are 

 present. Cases that are due to the presence of streptococci appear 

 to be benefited by the application of bacterins subcutaneously. An- 

 other form of treatment that has recently gained favor is the gentle 

 inflation of the affected quarter or quarters of the udder by means of 

 the milk-fever syringe used for inflating the udder in cases of milk 

 fever. This method is to be tested more fully. 



DOUKINE. 



The complement-fixation test has continued to be extensively em- 

 ployed for the diagnosis of dourine, 49,585 samples of serum being 

 tested, 1,225 of which gave positive reactions to the test, a percentage 

 of 2.47. 



During the year three colts were born to dourine mares at the 

 Bethesda experiment station. These mares had been shipped in from 

 Montana several years previously for observation and experimental 

 work. Complement- fixation tests on the serum of the colts demon- 

 strated the presence of natural immune bodies in the blood of these 

 animals, which, however, completely disappeared before the animals 

 had reached the age of 6 months. 



TESTS FOR TUBERCULOSIS. 



During the. past year 59 cattle reacting to the tuberculin test were 

 slaughtered under Federal supervision, in which no lesions of tuber- 

 culosis were found at the time of making a post-mortem examination. 

 Tissues from these animals were submitted to laboratory tests in 

 the Pathological Division, at which time investigations showed that 

 tubercule bacilli were present in the glands of 34 of the suspected 

 cattle, while none were detected in 25 of the specimens submitted. 

 It is worthy of note that in 4 reactors from the Pacific coast the 

 only visible lesions of tuberculosis present at time of slaughter were 

 nodules in the subcutaneous tissues of the legs below the knee or 

 hock. These nodules varied in size from one-fourth to three-fourths 

 of an inch in diameter, several nodules being jjresent on each affected 

 leg. 



DESTRUCTION OF TETANUS ANTITOXIN BY PROTEOLYTIC ENZYMS. 



As part of a general study of antitoxins, aimed at the determina- 

 tion of their chemical nature, their preparation in the i:)ure state, 

 etc., a study was made of the destruction of tetanus antitoxin by 

 proteolytic enzyms. Investigators do not agree as to whether anti- 

 toxins administered by mouth are destroyed in the digestive tract. 



