156 JOHNE^S DISEASE 



and killed shortly afterwards, show much the same 

 condition as is met with after a single injection. In 

 those killed at a later period the organs usually show 

 additional changes. The kidneys may, or may not, be 

 congested, and sometimes they present slight evidence 

 of cirrhosis. The lungs are usually normal in appear- 

 ance, but they may be a little cedematous. The spleen 

 is often somewhat enlarged, while the liver is more or 

 less fatty throughout. 



Animals that die after receiving a second intravenous 

 dose fifteen to thirty days after the first injection, and 

 those that succumb to repeated inoculations given at 

 short intervals, can be considered together. In these 

 cases post-mortem examination reveals an acute 

 nephritis, and sometimes the presence of fluid in the 

 peritoneal cavity. More rarely the pleural cavities 

 also contain fluid. There is usually fluid in the peri- 

 cardial sac, which is often distended to such a degree 

 that one has no hesitation in attributing death to the 

 presence of the fluid in this situation. The visceral 

 layer of the pericardium is often somewhat rough, but, 

 except for the presence of the fluid, there is not much 

 evidence of pericarditis. The lungs, in most cases, 

 are pneumonic. The liver may be congested, or pale 

 and fatty, according to the length of time that the 

 animal has survived. The spleen is generally normal, 

 though it may be slightly enlarged. The bladder is 

 usually distended with urine, whilst the lymphatic 

 glands, such as those of the axilla, are often congested, 

 sometimes intensely so. In none of these cases has 

 any pathological change been found in the intes- 

 tines, and nodular formations are absent from all the 

 organs. 



Microscopical Examination of the Organs. — The 

 kidneys are congested from the first day, and already 



