16 BULLETIN 1391, U. S. DEPARTMENT OF AGRICULTURE 
In the microscopic study the most noticeable changes were seen in 
the liver, kidneys, and blood. 
Liver. — The livers in all cases, except that of the horse, were 
fatty. The quantity of fat varied considerably in different animals, 
but it was of the same character in all and consisted of fine and 
large fat globules in practically all the hepatic cells. In the most 
pronounced cases practically the entire cell body was taken up with 
the fat, the nucleus and remaining cytoplasm being pushed to one 
side. In most instances the fat was evenly distributed throughout 
the lobule. The hepatic cells of the horse's liver were not fatty 
but contained large quantities of pigment. The cells in most cases 
Avere more or less swollen, the cytoplasm often coarsely granular, 
and the nuclei frequently very variable in size and sometimes 
shrunken or irregular in outline. Not uncommonly there were 
somewhat excessive numbers of leucocytes throughout the intralobu- 
lar capillaries, these having in some cases invaded the degenerated 
hepatic cells. There was wide variation in the quantity of blood 
present within the lobules in the different animals, apparently de- 
pending on the extent to which the hepatic cells were swollen. 
In addition to the degenerative changes in the hepatic cells there 
was an effect on the bile ducts. The small ducts in several cases 
were distended, giving the epithelium a low, flattened appearance. 
In some cases the cells were swollen and granular or vacuolated; 
less frequently some cells were exfoliated or necrotic. The connec- 
tive tissues surrounding such ducts was more or less congested and 
edematous and had become infiltrated with leucocytes. 
k This injury extended to the gall bladder, where it appeared in a 
more severe form. In the five cases sectioned, necrotic changes had 
occurred. Usually the epithelium had disappeared and the necrotic 
changes had extended to the other layers. Usually, too, congestion 
was pronounced, and in one case polymorphonuclear leucocytes were 
present in marked excess. These conditions are presumably asso- 
ciated with the bile changes noted at the autopsies and perhaps both 
have a bearing on the marked accumulation of pigment in the liver 
of the horse. 
Kidney. — More or less injury to the kidney parenchyma was pres- 
ent in all the animals. This was most marked in the convoluted 
tubules and consisted of a well-marked swelling and granular degen- 
eration of the tubule epithelium. In the most pronounced cases 
this granular cytoplasmic material largely filled the lumina of the 
tubules, and there was more or less disarrangement of the nuclei 
and loosening of the cells from the basement membrane. In many 
instances casts were present. These as a rule were hyaline in ap- 
pearance, but some contained exfoliated epithelial cells. 
In a majority of the cases some at least of the glomerular tufts 
were congested, or even hemorrhagic. Usually the congestion was 
accompanied with edema, and often the epithelial cells, both of the 
glomerular tufts and the capsule of Bowman, were swollen or 
granular. 
Congestion of the other portions of the kidney was not constant, 
but usually in each section individual or groups of injected capil- 
laries or minute hemorrhages were present. 
Blood. — Evidences of degenerative changes in the red blood cor- 
puscles were present throughout the various tissues, though they 
appeared most prominently in such organs as the spleen, liver, kid- 
