458 Veterinary Medicine. 



the different tissues and give a brown or reddish tinge to such as 

 are naturally white. limited blood extravasations are not un- 

 common especially in the more vascular organs like the muscles, 

 liver, spleen and kidneys. 



The liver is more or less congested and enlarged, friable, yellow, 

 or mottled yellow and red and exudes black blood freely when 

 incised. The bile is thick, viscid and dark green, as in cases of 

 experimental intravenous injection of haemoglobin, 



The spleen is also swollen and congested with blood, and the 

 pulp is very high colored from the excess of haemoglobin and 

 other products of blood destruction. The muscles of the croup 

 are usually the seat of visible lesions. There may be pallor, 

 oedema and swelling, but not unfrequently there are blood ex- 

 travasations varying in size from a pin's head upward and giving 

 a dark red aspect to the affected tissues. Under the microscope 

 the affected fibres are seen to have lost their transverse striation 

 and to have assumed a more or less granular or hyaline appear- 

 ance. Next to the gluteal muscles, these changes are frequently 

 found, in the muscles of the thigh (especially the rectus femoris, 

 and triceps extensor cruris), and in those of the loins (psoas, 

 ilio-spinalis, and longissimus dorsi). Exceptionally the pectoral 

 muscles are involved or even the abdominal muscles. A con- 

 siderable straw-colored oedema may be found in the inter- 

 muscular connective tissue. 



The red bone marrow primarily of the large bones of the limbs 

 (femur, tibia, humerus, radius,) and less frequently of other 

 bones, even of the vertebrae, is often the seat of intense vascular 

 congestion and even of hemorrhage. The medullary matter is of a 

 deep red or black color, and there is an abnormal accumulation of 

 red globules in various conditions of growth and destruction (red 

 nucleated corpuscles, fragments of corpuscles, colored granules). 

 Dieckerhoff considers the condition one of osteomyelitis, but it 

 seems to be rather a sudden, extraordinary exaggeration of the 

 processes of blood metamorphosis. Neumann found that when 

 the blood regeneration process is very active even the yellow 

 marrow may be changed into red, and this throughout all the 

 bones of the extremities. 



The kidneys are usually the seat of congestion, and black spots 

 of infarction, when the disease has lasted for twenty-four hours. 



