Caseating Lymph-Adenitis of Sheep, 399 



febrile ' symptoms, and of the common pyogenic germs, micro- 

 cocci, staphylococci, strepococci, bacilli, and by the presence of 

 the polymorphous, ovoid, dumb-bell or club-shaped, bacterium of 

 Preisz. From tuberculosis and glanders it is differentiated by 

 the absence of the delicate, slow staining, rod-shaped bacilli of 

 these diseases, and the presence of the bacterium of Preisz. The 

 clear, smooth, homogeneous surface of the fully formed capsule 

 in the caseous gland, also serves to distinguish it from the ir- 

 regular surface of the tubercle or glander nodule with its evi- 

 dence of peripheral congestion and advancement into surrounding 

 tissue, and the coincidence of lesions of old and recent date. 

 Again tuberculosis may be identified by the tuberculin test, and 

 glanders by the mallein test. From the nodular disease of the 

 intestines (CEsophagostoma) which it resembles in its yellowish 

 green color, it is clearly distinguished by its seat of election, 

 prefering as it does the lymph glands, and avoiding the intes- 

 tinal walls and mesentery. 



Treatment. In the case of superficial caseous deposits, a free 

 incision followed by an injection of zinc sulphate j4 oz., carbolic 

 acid I dram, and water i quart, repeated daily, until the cavity 

 heals by granulation, serves to repair the local lesions and to 

 reduce the number of caseating centres which are undermining 

 the general health. 



Prevention. This does not seem to have been attempted 

 mainly, perhaps, owing to the fact that the disease is not often 

 fatal, and that the affected sheep can be fattened and marketed. 

 Yet the prevalence of the affection in given flocks and pastures, 

 while others are spared, suggests its restriction by yearly, or at 

 least frequent changes of pasturage, the old pastures being 

 plowed up and subjected to a rotation of cultivated crops. 

 Water that has drained from the contaminated soils must be 

 avoided, and buildings and yards and, above all, racks and 

 troughs that have been used by affected sheep must be disin- 

 fected. In introducing fresh blood into a flock, or on to a pas- 

 ture hitherto free from the disease, care should be taken to avoid 

 infected flocks and pastures as the source of supply. 



