236 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE. 



on the ordinary culture media with negative results. A special 

 medium was then prepared from the mucous lining of the intestines 

 of a cow; and while it appeared that the implanted bacilli had mul- 

 tiplied in some of the tubes, the results were not sufhciently definite. 

 Another special medium, consisting of ground tubercle bacilli and 

 agar, was used for a series of inoculations, but hkewise failed to pro- 

 duce a growth. In all of these experiments the bacilh to be inocu- 

 lated on the culture media were secured by dissolving the infected 

 intestinal mucosa in an antiformin solution of sufficient strength to 

 destroy all other organisms present, it being assumed that as the 

 bacilli of chronic bacterial enteritis are not cUssolved readily by 

 strong antiformin solutions they retain their vitahty, as is the case 

 with tubercle bacilh. 



SWAMP FEVER. 



Leaving out of consideration the experiments wliich have not yet 

 been completed and those wliich have merely corroborated state- 

 ments already published, the results of the work of the past year on 

 swamp fever of horses have been largely negative. The observations 

 gathered, however, have suggested new lines of attack, which promise 

 to lead to more definite results. The investigation of tliis disease 

 has reached a stage where it is absolutely essential that an accurate 

 and early method of diagnosis be discovered, inasmuch as without 

 this it is impossible to determine accurately the value of any line of 

 experimental treatment, the progress of experiments in immunizing, 

 or to establish the identity of the disease in locahties where it has not 

 previously been recognized. Experiments having tliis object in view 

 are now in progress. 



Experiments have been undertaken to determine whether the com- 

 plement-fixation method of diagnosis, which has been found so accu- 

 rate with, glanders, can not be utihzed also in swamp fever. For the 

 antigen, shake extracts were prepared from the spleen, hver, and 

 heart muscle of an animal dead of the disease. These different 

 extracts were employed in dilutions established by titrations. The 

 complement-fixation test was then applied ^vith sera of horses affected 

 with swamp fever and also with sera of horses suffering from other 

 diseases, as well as with sera of normal horses. The results obtained 

 showed that a partial fixation of the complement had taken place in 

 all tubes containing serum from horses affected with swamp fever, 

 while in all other tubes complete hemolysis was present. The fix- 

 ation was most pronounced in the tubes in wliich the spleen extract 

 had been used as antigen. Further experiments will determine 

 whether it will be possible to employ this test for the diagnosis of 

 swamp fever, as the limited number of cases examined do not war- 

 rant dftfinite conclusions. 



The experiments in treatment with various medicinal agents have 

 not been satisfactory, because it has been impossible to determine 

 accurately the results of treatment. Owing to this lack of a diag- 

 nostic method, it has been impossible to determine the real value of 

 treatment even in cases where it had been apparently beneficial. 



TUBERCULOSIS INVESTIGATIONS. 



An opportunity was offered during the 3^ear to gain a valuable 

 amount of material for study from hogs that had been raised at an 

 insane asylum, where they had been fed upon garbage collected at 



