60 THE MILK SITUATION IN THE DISTRICT OF COLUMBIA. 



9. I will comply with all reasonable sanitary measures which are indicated 

 by the proper officials of the State or Territory wherein my herd is located, 

 or by the local board of health under whose permit I am disposing of dairy 

 products, or by the Bureau of Animal Industry. 



RESULTS OF TESTS AFFECTING DISTRICT MILK SUPPLY. 



Prior to October, 1907, according to Dr. John F. Anderson, direc- 

 tor of the Hygiene Laboratory of the Public Health and Marine- 

 Hospital Service, 1,147 cows in the District of Columbia were sub- 

 jected to the tuberculin test, and of this number 214, or 18.6 per 

 cent, responded. About the same time 1,059 cows from 51 herds in 

 Virginia, Maryland, and the District of Columbia, supplying milk 

 to Washington, were tested, of which number 160, or 15.1 per cent, 

 reacted. Even these figures fail to present a fair idea of the prevalence 

 of tuberculosis in the herds supplying milk to Washington, since ap- 

 parently only the owners of those herds who had reason to believe 

 their cattle free from tuberculosis permitted the tests to be made. 



In the fall and winter of 1908, 272 samples of the market milk of 

 Washington were injected, under the direction of Dr. Anderson, into 

 guinea pigs. Deducting from this number 49 of the animals that 

 died of causes attributable partly, at least, to the effects of other bac- 

 teria, 15 of the remaining 223 samples, or 6.72 per cent, contained suf- 

 ficient tubercle bacilli to cause typical tuberculosis in the inoculated 

 animals. It should be explained in this connection that the upper 

 stratum of cream was not used in these inoculations, and that it has 

 been shown that tubercle bacilli are more frequent in this layer than 

 in the bottom milk. It is reasonable to suppose, therefore, that if 

 both cram and sediment had been used the percentage of positive 

 results would have been much higher. This investigation disclosed 

 the further fact that the milk from 11 of 102 dairies in the District 

 contained tubercle bacilli, a percentage of 10.7 of the dairies exam- 

 ined showing tubercle bacilli in the milk supply to their customers. 

 These results, observes Dr. Anderson, are sufficiently emphatic to 

 show the necessity for the enactment and rigorous enforcement of a 

 law requiring that all cows supplying milk to the District of Colum- 

 bia be tuberculin tested by a competent veterinarian, and that those 

 animals which respond be disposed of in such manner that their milk 

 may no longer be a source of danger to the community. 



It was estimated in 1909 by Dr. John R. Mohler, of the Bureau of 

 Animal Industry, Department of Agriculture, that from 15 to 25 per 

 cent of all the cows supplying milk to the District of Columbia were 

 tuberculous, and no less an authority than Dr. Melvin, Chief of the 

 Bureau of Animal Industry, is responsible for the statement that 

 tuberculosis existed to a very considerable extent up to the time of 

 the general application of the tuberculin test to all cattle in the Dis- 

 trict of Columbia. Of 1,701 cattle tested with tuberculin, 319 reacted 

 to the test that is to say, gave evidence of tubercular infection and 

 2 additional cattle were held as suspects for testing at a later date, 

 about 19 per cent of all animals tested proving to be tuberculous. 



During the period from April, 1907. to June, 1909, inclusive, the 

 Bureau of Animal Industry supervised the testing of 2,471 cattle in 

 herds supplying milk to the District of Columbia. These tests gave 

 377 reactions, showing more than 15 per cent of the cows to be tuber- 

 culous. In Virginia, from July 1, 1909, to June 30, 1910, 899 cattle 



