106 



How FAR MA.Y A COW BE TUBERCULOUS BEFORE HER MILK BE- 

 COMES DANGEROUS AS AN ARTICLE OF FOOD ? H. C. ErNST, M. D. 



(pp. 13-24). — This is a preliminary report on investigations undertaken 

 under the aus])ices of the Massachusetts Society for Promoting Agri- 

 culture. The infectious character of tuberculosis is discussed with spe- 

 cial reference to the question whether the milk from cows with no defi- 

 nite lesion of the udder can be shown to contain the virus of tuber- 

 culosis. It is urged that, " as is well known, one seventh of the human 

 race approximately perish from this disease." Among the means by 

 which the virus is spread " are undoubtedly the excreta — more espe- 

 cially the sputum — from persons affected with the disease," and 

 " the ingestion of food materials coming from the domestic animals, 

 especially the flesh and milk of cattle." Experiments were conducted 

 by the author with cows especially selected and kept in frame build- 

 ings which were in a healthy locality and had been very carefully 

 cleaned and disinfected. Only the main features of the experiments 

 are reported in this bulletin.* 



All of the inoculation experiments and most of the microscopic work have been 

 done in the bacteriological laboratory of the Harvard Medical School, some of the 

 microscopic work at the Society's laboratory in Boston, whilst the feeding experi- 

 ments have been done and the experimental animals have been key»t at a farm in the 

 country devoted to this especial purpose, and situated amoug the healthiest possible 

 surroundings. Nothing has been set down as the result of microscopic observation 

 that I have not myself verified, and every portion of the work has been carried out 

 under the most exacting conditions and with every possible precaution against con- 

 tamination. * * * The observations have been carried on over a long space of 

 lime, and were made as follows: The milk was taken from the cow in the morning 

 or evening, as the case might be — the udders and teats having just been thoroughly 

 cleaned. The receptacle was an Erlenmeyer flask, stoppered with cotton wool and 

 thoroughly sterilized by heat. The s])ecimen was taken at once to the laboratory, 

 there placed in couical glasses, with ground-glass covers — the whole of these having 

 been carefullj' cleansed beforehand — and then allowed to stand in a clean refrigerator 

 for twenty-four to forty-eight hours, aud sometimes for seventy-two hours. 



At the end of that time from ten to twenty cover-glass preparations were made 

 from various parts of the milk or cream. These were stained after Ehrlich's twenty- 

 four-honr method, with fiichsin .and methylene blue as a contrast color, and then 

 searched with an immersion lens. 



[The examination was completed for one hundred and fourteen samples of milk ft'om 

 thirty-six cows,] all of them ])resenting more or less distinct signs of tuberculosis of 

 the lungs or elsewhere, but none of them having ma.rked signs of disease of the udder 

 of any kind. Of these samples of milk there were found seventeen in which the 

 bacilli of tuberculosis were distinctly present; that is to say, the actual virus was 

 seen in 10 [nearly 15] per cent of the samples of milk examined. These seventeen 

 samples of infectious milk came from tea diflferent cows, showing a percentage of de- 

 tected infectiousness of 27.7 per cent. 



These percentages are thought by the author to be clearly within 

 the limits of accuracy, since the amount of dilution greatly diminishes 



* The details maybe found in the Transactions- of the Association of American 

 Physicians, Vol. IV, 1889. Austin Peters, D. V. S., veterinarian of the Massachusetts 

 Society for Promoting Agriculture, Dr. Henry Jackson, and J^angdon Frothiugham 

 were associated with the author in this work. 



