166 THE MILK SITUATION IN THE DISTKICT OF COLUMBIA. 



the giving off of milk physically changed; from repeated diarrhea and discharge 

 from the vagina; from the repeated distension of the rumen with gas; from 

 cough and physical signs of lung disease, these pointing to tuberculosis. 



5. Unless tubercle bacilli be present in an article of food, be it milk or flesh, 

 such an article of food can not in any sense be considered a source of tubercular 

 infection. 



6. There must be a tubercular lesion of the udder in order that milk may be 

 contaminated with tubercle bacilli in sufficient numbers to be dangerous to man. 



7. Even if a clinically sound cow shed tubercle bacilli in her feces, which is 

 unlikely, the enforcement of proper rules governing cleanliness would eliminate 

 infection from such an alleged source. 



8. Tubercle bacilli can be discharged in feces only in advanced cases of the 

 disease in which there are open foci in the lungs or in the throat or in the 

 intestinal walls. Such cases would most likely be detected by clinical exami- 

 nation. 



9. The elimination from dairies of all clinically diseased cows or cows show- 

 ing upon careful physical examination by competent and conscientious veteri- 

 narians disease of the udder removes all danger of infection of which we can 

 take cognizance under present conditions. 



10. A careful periodical inspection of all dairies by competent veterinarians 

 at proper intervals, with removal of cows affected, as stated under paragraph 

 9, is as ample a safeguard for the protection of the public health as we can look 

 for for some years to come. The line of progress has been defined above. 



11. Tuberculosis prevails in countries where dairy products are not used as 

 extensively as in other countries. 



12. New York, Boston, and other American cities, as well as British cities, 

 are materially lowering their death rates from tuberculosis without such a 

 drastic and premature ordinance as that under discussion, as the same has 

 been explained to me. 



13. There is at present no evidence that the bovine type of bacillus can be 

 transferred and assume the human type in the human body. 



14. The discharge of tubercle bacilli into the milk of cows may take place 

 abundantly in udder tuberculosis. In a small proportion of manifestly tuber- 

 culous cows without evidence of udder disease it may take place at times in 

 very small numbers. 



15. The factor of bovine tuberculosis in the human malady is not of such 

 importance that it should be permitted to imperil the proper execution of meas- 

 ures designed to relieve and cure the strictly human disease, or divert attention 

 from it as the chief evil. 



16. The digestive tract is not the exclusive or even predominating portal of 

 entry for pulmonary phthisis. It is highly probable that most cases are due 

 to inhalation or aspiration. 



17. In infants the bacilli probably gain entrance through all portals more 

 easily than later in life, and the disease becomes more easily generalized. 

 There are no rational grounds for believing that latency in infancy plays any 

 apreciable role in the disease of later decades, but ingestion probably does 

 play a much more important part in infantile tuberculosis, owing to habits and 

 susceptibility of this period of life, than has been granted heretofore. 



18. In view of the unsatisfactory conditions which have followed a compul- 

 sory application of the tuberculin test, in the destruction of animals, attention 

 has been diverted from tuberculin as a guide, and an effort has been made to 

 eliminate only those animals which discharge tubercle bacilli. 



PASTEURIZATION. 



QUESTION 1. At what temperature should pasteurization be accomplished? 



ANSWERS. 



Pasteurization should be performed by heating the milk to not less than 

 140 F. for not less than 20 minutes and rapidly cooling it. For commercial 

 operations it would perhaps be well to require either a slightly higher tempera- 

 ture (145 F.), or a little longer time (30 minutes) in order to be on the 

 safe side. The so-called " flash " process of commercial pasteurization is not 

 regarded as reliable. (Chief Bureau of Animal Industry.) 



