DISEASES OF THE OX AND SHEEP. 



221 



When a tubercle is broken up, and inspected with the aid of 

 the highest powers of the microscope, five or even more giant- 

 cells provided with nuclei, and smaller cells, also with nuclei, 

 may be seen. These giant-cells are roundish and transparent, 

 and their oval nuclei, which may be as many as forty in number, 

 are arranged around the inner surface of their circumference. 

 These cells may be about l-200th of an inch in diameter, and 

 seem to have no cell-wall. The nuclei are not acted upon by 

 acetic acid, and each is said to be provided with a bright nucleolus, 

 which latter, however, is not seen in the above figure. These 

 giant-cells are easily destructible, and hence there may be 

 many free nuclei, the number of which is great in proportion 

 to the rapidity of the disease. In each of the above figures the 

 tubercle bacilli are well seen. 



Fig. 25. 



From a section through tuberculous deposits in the lung of a cow. Two 

 giant-cells and two small cells, all containing tubercle-bacilli, are seen. Magni- 

 fying power 700. (After jST/ezH.) In each of the two giant-cells the tubercle- 

 bacilli are seen to be arranged in a circle. 



Our readers will not be surprised that we have laid especial 

 stress on this most serious disease. It will be readily seen 

 why, on coming to tuberculosis in our list of diseases of the ox, 

 we resolved to treat the subject in detail. Not only is it the 

 case that large numbers of the cattle in this country are carried 

 off annually by this insidious and death-dealing, yet interesting, 

 malady ; but it is also true that great damage is liable to result 

 to the oxen of England by a tendency which, one may think, 

 only requires pointing out in order that it may be guarded 

 against — we mean the breeding from diseased cattle. There is- 



