134 MICRO-ORGANISMS AND DISEASE. [CHAP. 



From these cultivations new cultivations may be made and 

 carried on through successive generations, all cultures behav- 

 ing in the same manner ; and in all of them the rods only 

 are present, and show exactly the same changes as in the 

 parent culture. 



The smallest droplet of any of these cultivations produces 

 the disease in pigs, mice, and rabbits. The mice and rabbits 

 die with exactly the same appearances and with the same 



FIG. 65. BLOOD OF FRESH SPLEEN OF A MOUSE THAT DIED OF SWINE PLAGUE. 



1. Blood discs. 



2. A large nucleus. 



3. Groups of minute bacilli. 



4. Long bacilli. 



5. Dumb-bells of bacilli. 



Magnifying power 700. (Stained with gentian violet.) 



anatomical lesions as when they are inoculated with material 

 directly taken from the diseased organs of a pig dead of swine 

 plague. Those animals generally die on the fifth, sixth, or 

 seventh day, and on post-mortem examination show a charac- 

 teristic swelling of the spleen, a characteristic disease of the 

 liver (chiefly coagulative necrosis of tracts of the liver tissue), 

 and inflammation of the lungs. 



Inoculations of suitable sterilised nourishing fluids made 



