DISEASES OF CATTLE. 143 



ions in regard to the origin of tliis disease are divided, but 

 it is certain that it is contagious, for the following reasons : 

 Pleuro-pneumonia may arise from itself, or may be trans- 

 ferred by contagion to healthy animals. The latter is often 

 the case. The spontaneous formation of pleuro-pneumonia 

 emanates from very different causes — 



1. From the unfavorable influence of the atmosphere, 

 especially during the spring, mostly in changeable, cold 

 and damp weather, when the animals take cold. 



2. By permanent feeding with artificial food. 



3. By spoiled food, such as sour, mouldy, musty hay, 

 rotten roots or bulbs. 



4. By drinking unclean water. 



o. By keeping them without exercise or motion, especially 

 in overcrowded stables. 



6. By careless attendance to the animal, want of clean- 

 ing the stables, etc. 



7. By importation of untanned hides, etc. 



8. By cattle imported from other countries, particularly 

 in times of war, etc. 



9. From low-situated pastures with marshy bottoms. 



At the dissection of the animals we find in the carcass 

 the most remarkable changes in the cavity of the breast. 

 On cutting the breast, in most cases a large quantity of 

 yellow water bursts forth, in which more or less yellow 

 flakes or lardaceous articles are swimming. The lungs are 

 covered with the same thick and lardaceous films, and ad- 

 here on one or both sides to the ribs, but always more to 

 the right than to the left side. The lungs are partially 

 or entirely callous, greatly distended and heavy, so that 

 they weigh twenty to forty pounds and even more, whereas 

 a sound lung only weighs from four to five pounds. On 

 cutting the hardened part of the lungs it looks like marble, 

 the dark, red-colored mass of the lung being interwoven by 



