338 CONTAGIOUS DISEASES. 



These abscesses often appear, without any premonitory signs 

 of ill health, as hard swellings, which sooner or later suppurate 

 imperfectly, or burrow deeply in all directions ; at first they are 

 not painful, but often become very much so, and may multiply 

 rapidly, appearing between the jaws, on the neck, about the eyes, 

 lips, and nostrils, and occasionally upon other parts of the 

 body, causing swelling, preventing the sheep from feeding, and 

 rendering the breathing difficult, and snoring. In some instances 

 swelling of the face and discharge from the nose are observed 

 previous to the development of the tumours. 



Young animals, particularly young fast-growing tups, if 

 exposed to cold, are especially subject to this disease, but older 

 animals of both sexes, as well as lambs, are not exempt. 



If these abscesses are opened, the quantity of pus contained 

 within them, not always commensurate with their size, is 

 generally thick, and flows tardily, but afterwards becomes 

 thin, and more or less ichorous ; it is surrounded by a thick 

 sac of low fibrous material, like the walls of an old ulcer, and 

 sinuses are often found running from the cysts into the sur- 

 rounding structures. Microscopically examined, the pus is 

 found to consist of ordinary pus cells, rather shrivelled in 

 appearance, but showing little or no tendency to caseation, and 

 the tubercular bacilli are absent, but the pus may be loaded with 

 the cocci of suppuration. In many instances the tumours 

 undergo little or no change for two or three years, the sheep 

 seemingly suffering no inconvenience ; but in other cases the 

 animal loses flesh rapidly, the wool falls off in patches, 

 symptoms of fever manifest themselves, a cough is now and 

 then heard, and the sufferer dies from exhaustion, anaemia, and 

 sometimes dropsy. The flesh in this advanced stage is pale and 

 watery, but if an animal l^e slaughtered in the earlier stages it 

 is fairly good. 



The jjost mortem appearances are often quite local, merely 

 collections of pus in the various thick-walled abscesses observable 

 before death ; the pus will, however, be found to have burrowed 

 from the abscesses in various directions into the surrounding 

 tissues. Now and then some degree of ulceration of the nasal 

 mucous membrane may be detected, and abscesses found in the 

 lungs, but these two latter conditions are by no means constant. 

 Strumous abscesses in sheep, or the conditions which lead to 

 their formation, do not seem to be hereditary, as the stock 



