152 THE MILK SITUATION IN THE DISTRICT OF COLUMBIA. 



To about 95 per cent. (Health officer Kansas City, Mo.) 



In the tests in Lynchburg it has been found reliable in every instance. 

 (Health officer Lynchburg, Va.) 



Entirely so in the hands of a skilled veterinarian. Of course cases that can 

 be detected by physical examination should not be tested. (Health officer 

 Montclair, N. J.) 



Two c. c. per cow unless private tests have been made, and then 3 c. c. Out 

 of 8,000 tests not one mistake has been made, i. e., each cow killed showed 

 tubercular lesions. (Health officer Portland, Oreg.) 



Most reliable test we have. Ninety-seven per cent of cases can be detected. 

 (Health officer Providence, R. I.) 



Almost absolutely so. (Health officer Richmond, Va.) 



Ninety-seven per cent. (Health officer Rochester, N. Y.) 



Ninety-eight per cent. (Health officer Seattle, Wash.) 



Only by competent men, backed by State authority. (Health officer Syracuse, 

 N. Y.) 



Practically absolute when tests are studied with good judgment as to other 

 associated conditions of the animal. (Health officer Topeka, Kans.) 



According to scientists, about 98 per cent of condemned cattle are infected. 

 (Straus Laboratory, Washington, D. C.) 



Not sufficiently perfected to be infallible. (John Thomas, Ednor, Md., presi- 

 dent, Milk Producers Association.) 



Uncertain. Best authorities agree that the tuberculin test is not a reliable 

 diagnostic for tuberculosis. (Sharon Dairy, Washington, D. C.) 



We believe it has been shown that the tuberculin test is reliable to show that 

 the cows either have or have had tuberculosis in over 90 per cent of the cases. 



In order to be able to rely upon the tuberculin test we believe that all the fol- 

 lowing conditions must be strictly complied with : 



(1) The owner of the cow must be absolutely honest toward the veterinarian. 



(2) The test must extend over a period of several months, so that the possi- 

 bility of previous dosing of the cow can be eliminated. 



(3) The state of health of the cow and the conditions surrounding it must 

 be known to the veterinarian by personal examination. 



(4) The veterinarian must be skilled in administering tuberculin. (NOTE. 

 We believe that only a very few veterinarians and mostly those who have had 

 great experience are competent to administer the dose and get accurate results.) 



(5) The tuberculin must have been prepared with the greatest care, and the 

 veterinarians must know what the strength of the tuberculin is. (NOTE. Com- 

 mercial tuberculin is of varying strength and sometimes impure.) 



(6) The dose of tuberculin must be of the right amount and strength. If 

 there is an overdose of tuberculin the cows, although healthy, would react. 

 (NOTE. The tuberculin test is so delicate and so liable to err that it should be 

 used to corroborate /the clinical evidence of disease and not as a sole test of 

 the presence of the disease in apparently healthy cows.) 



(7) Animals suffering from diseases other than tuberculosis will react upon 

 the injection of tuberculin. 



We believe the following are the inaccuracies of the tuberculin test : 



(1) A cow which may have had at some time during her life a slight infec- 

 tion of tuberculosis and had entirely recovered, and the lesion calcined and 

 healed, will still react to the tuberculin test, although she is perfectly healthy 

 at the time of the test. 



(2) A diseased cow which has been injected with tuberculin within a period 

 of three months previous to the test will not react. 



(3) A diseased cow, which is fed with febrifuge (antiperitic), just before the 

 dose, will not react. 



(4) Healthy cows, if excited at the time of the test, will react. 



(5) If the test is administered in hot weather, and the cows are driven from 

 the fields into the stable during the time of the test, healthy cows may react. 



(6) In advanced cases of tuberculosis no reaction is obtained upon the injec- 

 tion of tuberculin. 



(7) A cow may not react if infected during the period of incubation, which 

 ranges from 8 to 50 days. 



(8) It may be that timothy bacilli will cause reaction, and those bacilli, 

 so far as we know, are harmless. 



It is believed by many authorities that the injection of tuberculin is dan- 

 gerous to healthy cows, in that it may cause latent tuberculosis to develop into 



