10 BULLETIN 969, U. S. DEPAETMEITT OF' AGRICULTURE. 



In one animal congestion was present in the duodenum, jejunum, 

 and ileum; in another this condition was found only in the ileum 

 and cecum ; while the third had a hemorrhagic area in the duodenum 

 and minute hemorrhages in the ileum. The pancreas was congested 

 in one. The livers of two were noted as pale. The kidneys were 

 congested in one and hyperemic in another. 



In general, the autopsy findings corresponded very well to 

 those seen in animals poisoned by the other whorled milkweeds. 



PATHOLOGICAL CHANGES IN TISSUES. 



The autopsies in 2 of the 3 sheep killed with Asclepias mexicana 

 in 1920 were commenced within 30 minutes after their deaths. 

 These were Sheep 590 and 595. Sheep 610 was dead much longer be- 

 fore the autopsy and well-marked post-mortem changes had occurred 

 in the tissues. The following description of the pathological changes 

 is based on Nos. 590 and 595. The material was fixed in 10 per cent 

 formalin and stained with Delafield's hematoxylin and eosin, except 

 specimens of the cerebellum of Sheep 590, which were fixed in alcohol 

 and stained with various nerve-cell stains. Formalin-fixed material 

 of the cerebellum of both sheep was stained with toluidin blue, Nissl 

 stain, polychrome methylene blue, neutral red, and other stains. 



Liver. — The hepatic cells in both animals had undergone well- 

 marked degenerative changes which differed slightly in the two 

 cases — those of Sheep 590 were very fatty, the nuclei, however, 

 taking the stain well, while the hepatic cells in the liver of Sheep 

 595 had a very granular and swollen cytoplasm. In the liver of 

 Sheep 595, too, certain hepatic cells, singly and in groups, showed 

 marked affinity for eosin. In the capillaries of the liver lobules of 

 both there was an unusually large number of leucocytes, especially 

 polymorphonuclear. These were often in small clumps, covering 

 the area of half a dozen or more hepatic cells in the liver section 

 of Sheep 590. 



The livers of both animals had congested and edematous areas 

 with some small hemorrhages. This was most noticeable in one 

 preparation of the liver of Sheep 590, where the congestion was 

 severe just beneath the capsule and had compressed the liver cords. 



Many veins, both portal and hepatic, were empty, while others 

 contained much granular detritus, brownish pigment granules, de- 

 generate erythrocytes, and sometimes endothelial cell nuclei and 

 numerous leucocytes. Rarely hepatic cells were found in the sub- 

 lobular veins. The wall of the congested portion of the common 

 bile duct in both cases had undergone necrotic changes extending 

 well into the mucosa. The epithelial layer was gone. 



Kidneys. — In both kidneys there was congestion of the straight 

 veins of the medulla and areas of capillary congestion in the cortex 

 with a few small hemorrhages betweeen the tubules. The principal 



