No. 6. DEPARTMENT OF AGRICULTURE. 131 



Tubrrciilin. 22,655 c. c. of concentrated tuberculin have been made, requiring 

 the inoculation of 1,979 flasks each containing 200 cubic centimeters of glycerine 

 bouillon. No change in the preparation of the tuberculin was made, but various 

 experiments were carried out, the results of which, however, did not alter the 

 original method. The difference in growth of the tubercle bacillus was studied 

 upon bouillon to which 1 per cent, of sodium phosphate was added in place of 

 ] per cent, sodium chloride. Dorset in his article upon the growth of the tubercle 

 bacillus upon these two media stated that the growth was more vigorous upon 

 the bouillon containing the sodium acid-phosphate. This was found to be true so 

 far as exuberance of growth is concerned, but in weighing six week-old growths 

 from each medium we found them to weigh practically the same. An attempt 

 was made to determine the difference in the toxicity of the tuberculin made from 

 a non-virulent human tubercle bacillus culture (W) and a virulent bovine tuber- 

 cle bacillus culture (H). A separate lot of tuberculin was made ^rom each cul- 

 ture, and tested upon healthy and tuberculous guinea pigs. No marked differ- 

 ence could be noted from the results obtained. Good reactions were obtained 

 with each tuberculin upon tubeculous cattle. Tuberculin for the ophalmo-tuber- 

 culin test, has been prepared. 



Tuberculosis laccinc. The preparation of this vaccine is now a matter of 

 routine, the technique of which has been improved upon considerably during the 

 past year. 



Mullein. 1,840 c. c. of concentrated mallein have been made. The prepara- 

 tion of mallein still proves to be a tedious task. So few of the strains of cultures 

 isolated prove of the proper virulence, or retain that virulence during the eight 

 to nine weeks a culture should be permitted to grow. 



Aullirax raciiiir. 1,575 doses of vaccine No. 1 and No. 2 were sent out. The 

 anthrax vaccine cultures were tested out early in the year upon white mice, 

 guinea pigs and rabbits, and were properly standardized. 



Spcriinnis sent for dkif/nosis. During the year S65 speciments were received 

 at the laboratory for diagnosis, of which 9 came in such badly decomposed con- 

 dition as to make an examination impossible. 



Ifabies. Ill heads were received for the examination of rabies, including 90 

 dogs, of which 71 were positive, 15 negative and in 4 decomposition interferred 

 with the examination; 4 horses, 1 positive, 3 negative; 15 cows, 10 positive, 5 

 negative. 



The diagnosis was made by the use of three methods: 



(1) Smears and sections of The various brain structures were examined for 

 Negri bodies. 



(2) Sections were examined for the presence of endothelial cell projections of 

 the blood vessels and lymph-sacs around the ganglion cells. 



(3) Animal inoculations. 



The third method was used as a decisive test when the results of the first and 

 second were doubtful. 



Prom the work during the year 1906 upon rabies, the diagnostic value of the 

 Negri bodies was proven beyond question, and as a result the following rules 

 were found to be reliable to in making the diagnosis during the year: 



(1) Negri bodies demonstrated, diagnosis positive. 



(2) Suspicious bodies in fresh brains with marked ganglion proliferation 

 changes, diagnosis positive. 



(3) Negri bodies not demonstrated, and no ganglionic proliferation changes, 

 diagnosis very probably negative. Animal inoculation made. 



(4) Negri bodies not demonstrated and ganglionic proliferation changes pres- 

 ent, diagnosis uncertain. Animal inoculation made. 



The use of smears has proven the most rapid and efBcient method in the 

 demonstration of the Negri bodies. No special line of original work on rabies 

 was attempted, the work being carried out in a form of regular routine, which, 

 however, brought out some interesting facts in the diagnosis of this disease. 



Tuberculosis. 27 specimens were received for examination consisting of parts 

 of organs and growths from cattle. The existence of tuberculosis was demon- 

 strated in 14; 13 were found to be non-tuberculous. 



The diagnosis was made upon: 



(1) Tuliercle bacilli demonstrated in smears. 



(2) Animal inoculations. 



If, as frequently happened, the smears failed to reveal tubercle bacilli and 

 the animals inoculated died before it was possible for lesions of tuberculosis to 

 develop, the diagnosis was then made, if possible, from the microscopic exam- 

 ination of the specimens. Aside from the diagnosis of tuberculosis, the vaccina- 

 tion work was carried on and Experiment 115 (U) and 115 (O) upon cattle were 

 completed. The rabbit experiment of Experiment 115 (O) was started but not 

 completed within the year. 



An experiment was carried out upon guinea pigs for the purpose of solving the 

 following problem: to determine the ability of the tubercle bacilli to pass 

 through the intestinal wall of healthy animals and the time required for them 

 to reach the lungs. 



Glanders. 132 specimens were received for examination; these may be di- 

 vided into two classes: 



(1) Blood from horses and mules suspected of glanders. 



