236 



OVINE CASEOUS LYMPH-ADENITIS 



genus Bacterium. It is aerobic, facultative anaerobic, stains 

 readily and does not produce spores. It develops readily on 

 agar when this medium is inoculated from the caseous material 



Fig. 56. Bacterium of Preisz. Bacterium 

 4. ocular (Gitruih). 



pus cells 1-12 obj. 



from the affected glands. It is pathogenic for mice, guinea 

 pigs and rabbits. The organism isolated by Gilruth seems to 

 have been more virulent than the one isolated by Norgaard 

 and Mohler. 



§ i6g. Symptoms. In the majority of cases no symp- 

 toms of any importance are observed in the affected animals 

 during life. The course of the disease is that of a chronic 

 affection and the pathological changes develop so slowly that 

 no general or local interference with the health of the affected 

 animals is observed in lambs and sheep that are bred and 

 raised for mutton and are marketed before they are two years 

 old. Only in breeding ewes and wethers does the disease 

 advance to a degree which makes it clinically recognizable 

 without the aid of manipulation. The affected animals upon 



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