130 DISEASES OF SWINE 



of discolored areas due to frost-bites, especially of the tips of the 

 ears. Reddening may take place from the presence of many skin 

 diseases, such as mange or urticaria. Simple dragging of the belly 

 on the ground, or the irritation produced by traumatic injuries 

 in stumpy pastures, also produces reddening of the skin, especially 

 along the belly surface. In noting the presence of areas of redness 

 due consideration must be given to these other possible causes as 

 well as the probabihty of their being due to cholera. 



LESIONS IN THE LYMPHATIC GLANDS 



Having completed the examination of the skin, we now take 

 the knife and make an incision from the inner side of the foreleg 

 down along the neck to the angle of the jaw on the same side. This 

 incision, if correctly made, will open to view the chain of lymphatic 

 glands known as the cervical glands, as well as the large gland 

 located at the angle of the jaw, known as the submaxillary gland. 



In hog-cholera there is a special tendency for hemorrhages to 

 take place into the substance of these glands. As a result, we 

 find that the cut surface of the gland, which is normally of a clear 

 grayish-pink color, becomes reddened and even black in color. 

 This discoloration may appear as a number of diffuse pin-point- 

 like red spots — petechial hemorrhages — or it may take the form 

 of a diffuse redness of the entire gland. 



The gland itself is also considerably larger than normal, due to 

 'swelling, and there is noted also a marked softening of the gland 

 substance. 



If we were to examine this gland in microscopic section we 

 would find that here, as in the skin, we have an enormous dilata- 

 tion of the blood-vessels, with, in many cases, a complete rupture of 

 their walls and the escape of their contents into the gland substance. 

 In many cases where there has been a very large amount of hemor- 

 rhage into the gland tissue, it is practically one mass of blood-clot. 

 In other cases we only find the small areas of hemorrhage scattered 

 throughout the substance of the gland. 



In practically every case the microscope will show a marked 

 enlargement of the individual cells which go to make up the gland, 

 and these cells will be found to be in a marked condition of degen- 

 eration with commencing death. In stained sections the individual 



