214 



THE DISEASES AND DISORDERS OF THE OX. 



disease will be set up in the intestinal tract. Our readers will 

 remember that in dealing with pleuro-pneumonia we pointed out 

 that the germs of the disease enter the system by the lungs, and 

 that these organs are chiefly affected. If the germs of the 

 disease are introduced into the tail, as in preventive inoculation, 

 the lungs are not affected, though probably the micrococcus is 

 distributed to all parts of the system. Similarly in tuberculosis, 

 we find that if the disease is induced by feeding an animal with 









Fig. 22. 



The above illustration represents the microscopical appearance of a section 

 taken from the same kidney as that from which the section represented in the 

 preceding picture was taken, (a) Large artery filled with caseous matter, and 

 iu it niimerous tubercle-bacilli. (h) Coat of artery. (c) Nuclei of the 

 tuberculous new growth, (c?) A Malpighian corpuscle. Magnifying power 

 about 500. 



tubercular matter, the organs which are first affected are the 

 intestines themselves, and that the infection gradually spreads 

 until at length the lungs are attacked. We have just seen above 

 that if the tubercular virus is introduced by inoculation, the 

 lymphatic glands near are first affected. If the disease is 

 propagated through the air, i.e. by breathing the germs, then 

 the lungs seem to be first affected, just as we should expect. 



