DISEASES OF THE OX AND SHEEP. 233 



wretched hygienic treatment and bad feeding to which unfortunately so many of 

 our poorer children are exposed, tuberculosis may be contracted as the result of 

 the ingestion of milk from tuberculous udders. 



A cow may have a tuberculous udder without the slightest falling off in the 

 general condition. The best way to detect tuberculous disease is to stain 

 specimens of milk, and then search with the highest powers of the microscope 

 for the tubercle-bacilli. The development of the tubercle in the udder is ex- 

 tremely rapid, and hence it would be well to have all cows which supply milk 

 examined every fortnight in order to see if the udders are affected or not. 



Dr. Woodhead and Mr. Hare have pointed out " that after one micro-organism 

 has completed its task, another may step in and continue the process of break- 

 ing down. How often has a patient suffering from a tubercular abscess of the 

 kidney or of the lungs succumbed at last (if not carried off by acute tubercular 

 disease) to pyaemia, and pyaemia in which the symptoms are exceedingly well 

 defined." 



Acute miliary tuberculosis must be looked upon as the result of spreading of 

 the infective material by the medium of the blood-vessels. In a series of 

 several cases of acute miliary tuberculosis Weigert was able to determine that 

 ulceration of the pulmonary vein had taken place. Ponfick previously had 

 supposed that the bacilli might pass from a tubercular thoracic direct into the 

 venous trunks, and thus to the general circulation. Probably both observers 

 were correct. Again, Coats points out that bacilli may pass into the minute 

 venous radicles in those glands wherein tuberculous changes are occurring. 

 Tuberculosis is a comparatively curable disease, and, as we gradually gain more 

 and more knowledge, it is probable that the death-rate may be materially 

 diminished. 



It is highly probable that human beings may become infected with tuberculosis 

 by means of the transmission of the bacilli through the medium of the milk or 

 flesh of cattle, or the flesh of swine. It may also be transmitted from a man 

 afflicted with tuberculosis to other persons. 



Weigert has shown that a giant cell is, in some cases, nothing more than a 

 collection of cells in which the bacilli are causing proliferation at the margin. 

 In the centre, fusion and degeneration take place, and the result is that a mass 

 of caseous material occurs in the centre, whilst prohferating cells, with bacilli 

 between them, are seen at the margin. Klein has seen the giant cells being 

 formed by means of the fusion of epithelial cells of the air-vesicles. The 

 presence of these giant cells seems to aft'ord evidence that the cells are making 

 a determined resistance against the inroads of the bacilli ; that they are slowly 

 giving way, and so limiting the area of caseation. In many cases where the 

 giant cells, with their rings of nuclei, are best marked, very few bacilli are to be 

 found, as they have been destroyed by the phagocytes at the margin, that is, by 

 the active cells with deeply-stained nuclei. In other cases, however, the bacilli 

 have taken the place of the nuclei at the margin of the giant cell, the boundary- 

 line in such cases being determined, for a time, by the basement membrane of 

 the tube in which the mass is formed. 



We are indebted for the following note to Mr. Tedbar Hopkin, F.R.C.V.S., 

 Manchester (vide The VeteriJiart/ Journal, Jan. 18Sd^ : — A friend of this gentle- 

 man was called to see a cow suffering from advanced tuberculosis. The cow 

 was killed, and a heifer, the daughter of this cow, being some time afterwards 

 slaughtered, was, hj post-mortem examination, found to have tubercles pervading 

 the viscera. This event was followed by a serioiis outbreak of tuberculosis in 

 the fowls on the same homestead, and also in the rabbits on the estate, large 

 umbers dying of the disease. In an adjoining village a rabbit-warren was 



