336 VETERINARY LECTURES 



as hardly greater than the hereditary transmission.' While agree- 

 ing with him on the milk and meat question, my experience leads 

 me to differ with him respecting the hereditary tendency of the 

 malady. Calves are born tubercular, and the problem to be solved 

 is, How do they become affected ? It cannot be by direct ingestion 

 or inhalation. Again, how can the fact be explained that the disease 

 is known to run in certain families of the human subject for genera- 

 tions, such families cohabiting with other families that remain free ? 

 And the same holds good in certain bloods of cattle. If the disease 

 itself is not directly transmitted at conception, then there must be a 

 hereditary diathesis or a hereditary predisposition conveyed, which 

 is well exemplified in the pearly flesh and apple-blossom cheeks of 

 some of our bonny lads and lassies. The ptomaines produced by the 

 bacilli may have a baneful effect on the germs of a future genera- 

 tion, rendering them liable to become, on development, a fruitful 

 seed-bed for the propagation, growth, and distribution of a new 

 series of tubercular bacilli. These bacilli, it may be taken for 

 granted, are not all that is required. There must also be a suitable 

 seed-bed, replete with all the necessary conditions for fostering and 

 developing the growth of the bacilli. Although I am a strong 

 advocate tor plenty of fresh air, sunshine, and proper ventilation, all 

 of which are highly necessary for giving healthy tone to the struc- 

 tures of the body, yet they will neither cure nor prevent consump- 

 tion as long as the tubercular bacilli and suitable subjects are 

 present. As a proof of this, the cows in New Zealand suffer as 

 much from tuberculosis as those in the British Isles, yet they have 

 plenty of sunshine and fresh air, living as they do in the open air, 

 with the blue canopy of heaven as their covering. Though tuber- 

 culosis cannot be cured under the open-air treatment, it may be 

 arrested ; but the patient has to be well cared for, and is liable to 

 have a relapse at any moment. With reference to the air-space so 

 much talked about, it is not so much the matter of cubic feet of air 

 as it is of proper ventilation. If the latter is not good the air-space 

 avails little, as an infectious disease will spread as quickly in an 

 unlimited air-space as it can in a limited one. 



