118 TUBERCULOSIS. 



and even intermittent freezing and melting, did not interfere 

 with the transmission of the disease by means of the bacillus. 

 Other observers have demonstrated that the bacillus remains 

 virulent after it has been exposed, in sputum, for forty days, and 

 even after 18G days if it is carefully protected from the action of 

 the air." It seems probable that cattle as a rule are infected by 

 each other, the result in that case being an attack of ordinary 

 bovine tuberculosis ; but the acute form which we sometniies 

 hear of as suddenly appearing in certain localities, if a reliable 

 opinion may be formed from the experiments recorded by Wood- 

 head, is in all probability brought about by the copious expectora- 

 tions of some phthisical patient whose ejected bacilli, protected 

 from the air by their coating of sputum for more than a month 

 in dry weather, retain their vitality and adhere to the blades 

 of grass which in a fully-stocked paddock are liable to be sooner 

 or latter eaten by the cattle. In town and suburban dairies the 

 danger which the cattle are exposed to is very much greater. 

 No precautions are taken to prevent phthisical persons from 

 engaging in dairy work, and if the bacilli of tuberculosis are 

 conveyed to children and others in the milk, it is by no means 

 improbable that these have gained admission to the cans through 

 the handling of them by persons whose tuberculous condition 

 makes them a centre from which the disease is distributed. Nor 

 should it be forgotten that the material witli which dairy cows 

 are fed, if handled by tuberculous persons, may convey the 

 bacilli from them to the cows. Whatever, therefore, may be 

 the danger to human beings of infection from cattle, it is obvious 

 that this is small as compared with that of infection from each 

 other, that cattle are exposed to a similar danger of infection 

 from man, and that in this case it is the acute form of the 

 disease which commonly develops itself and causes very great 

 suffering to its bovine victims. 



Hitherto we have been asked to regard this important 

 question as one which is closely associated with the public health. 

 I go further than this ; for the authorities who tell us that we 

 vuvj contract tuberculosis indirectly from cattle by using unboiled 

 milk and insufficiently cooked flesh, have also jiroved by recorded 

 experiments, the reliability of which nobody disputes, that cattle, 

 •dogs, and fowls are attacked by tuberculosis in its worst form if 



