THE MILK SITUATION IN THE DISTRICT OF COLUMBIA. 153 



active tuberculosis, or so weaken its resistive power that it becomes more 

 liable to take the infection. 



We consider, however, that the greatest objection to the reliability of the 

 tuberculin test to show that the cow is diseased with active tuberculosis is the 

 fact that cows which have practically recovered from the infection, where the 

 lesions are encysted and calcified, react as typically as cows that are actively 

 diseased. 



We have the results of a tuberculin test and a post-mortem examination of 

 reacting animals of two herds, made officially under the New York State De- 

 partment of Agriculture, which may be stated generally as follows : 



In one herd 44 cows were tested and 24 reacted. None of them had any 

 lesions of the udder. Of these 24, 4 carcasses were condemned as having 

 generalized tuberculosis and were tanked; the remaining 20 carcasses were 

 passed as fit for food; in all but one there was not more than one or two 

 glands affected, and all of these glands calcified. In one (which was par- 

 ticularly picked out for special demonstration and slaughter at the Tompkins 

 County Fair at Ithaca), when it came to be slaughtered no lesions were found 

 whatever, so that the net result of the condeming of 24 cows of that herd was 

 that 4 of them were badly affected. 



Two of these cows had been condemned on physical examination before the 

 examination of the tuberculin test,- so that had they been taken out of the 

 herd the tuberculin test would have condemned 50 per cent of that herd, and 

 of that 50 per cent only 1 per cent were badly affected. 



In the second herd there were 56 cows and 10 calves tested. Eleven cows 

 and four calves passed the tuberculin test. Eight animals were selected by 

 physical examination as being infected before testing by tuberculin. Fifty-one 

 were slaughtered. In 4 of them no lesions could be found, and 39 carcasses 

 were passed for food, and 6 were condemned as having generalized tuber- 

 culosis, and the carcasses were tanked. In 28 all the lesions were found to be 

 calcified ; the cows were fine, big cows and good milkers. 



These two herds were not selected, but were herds which were tested and 

 condemned under the New York State department of agriculture. We had 

 nothing to do with it, but we were allowed to attend and to take note of the 

 results. 



It is only fair to say that the United States Government experts claim that 

 no one can tell when cows that contain calcified lesions may not develop 

 active tuberculosis again under unfavorable conditions or sickness, such as 

 pneumonia, and that therefore they are dangerous and should be removed from 

 the herds. 



We hold, however, that in view of the fact that so many human beings have, 

 at some time or other, been actively affected by tuberculosis, and have re- 

 covered and lived long and useful lives and died of other diseases, we think 

 it is but fair to give any cow whose vitality was sufficient to calcify the 

 lesions the benefit of the conclusion that probably, if she had not been killed, 

 she would have remained a valuable producer of milk for a number of years 

 unless, of course, taken sick. In that case she would not be fit to be a milk 

 producer, but such sickness would be evident to the dairyman. 



Therefore we believe, after a very careful study of the whole situation, 

 that the reaction following the tuberculin test is not a reliable means of de- 

 termining whether the cow is then suffering from active tuberculosis. (Borden's 

 Condensed Milk Co., New York, N. Y.) 



In 3,000 tests less than one-half to 1 per cent of the temperature readings 

 have been doubtful. All reactions confirmed by post-mortem, and have no 

 reason to suppose that in more than three cases have infected animals passed 

 as sound. (Walker-Gordon Laboratory, Washington, D. C.) 



Almost absolute. (Dr. V. C. Vaughan, Ann Arbor, Mich.) 



Very reliable when carried out with intelligence and care. (Dr. S. C. Pres- 

 cott, Boston, Mass.) 



Reliable in over 97 per cent of the cases when tested by competent men. 

 (Health officer Los Angeles, Cal.) 



Very great extent. ( J. M. Houston, White Cross Milk Co., Washington, D. C.) 



If carefully done, almost infallible. According to Bang, error is only 3.3 per 

 cent. (Health officer San Francisco, Cal.) 



The reliability depends upon the skill and honesty of the person making the 

 test. (Health officer St. Joseph, Mo.) 



About 96 per cent. (Health officer Wheeling, W. Va.) 



