REAdtrON OF SELACHII TO INJECTIONS 123 



most of them have suffered chromatin changes. The blood- 

 vessels in the kidney of this animal contain a large amount of 

 debris. 



In the first animal there are present in the blood-vessels of 

 the degenerated region of the kidney many nuclei of a very 

 peculiar shape (fig. 26). This may indicate an attempt at 

 amitosis by phagocytes, probably in the spleen and gills. One 

 cannot make out any cytoplasm, so that if a cell wall is present 

 it is tightly adherent to the nucleus. On the whole, the kidney 

 is less seriously injured in the uranium series than in the chro- 

 mate or tartaric. However, the size of the dose of the toxin 

 and the time element are probably the most important factors 

 in the amount of injury produced. 



In the anterior region the tubules show no signs of degenera- 

 tion in some sections, and very few in any. The congestion is 

 mild as compared with that in the posterior region. A few 

 tubules stain poorly and their cytoplasm is quite granular. 



e. Liver. The liver and gall-bladder are practically uninjured 

 even in the third animal. In all sections a few nuclei of the 

 hepatic cells and ducts are hyperchromatic and shrunken, but 

 not in more than 12 per cent at most. In the third animal 

 (which received a large dose and which died before autopsy) 

 the ducts contain considerable debris, and a few of their cells 

 are very slightly cytolysed. 



d. Spleen. The spleen is congested in every specimen. The 

 sinuses are dilated and contain granular debris, which probably 

 has come in from the kidney. The endothelial cells of the 

 sinuses contain these granules and their nuclei are often swollen 

 and hypochromatic. In the first animal (fig. 27) there are many 

 peculiar-shaped nuclei which resemble those seen in the kidney 

 and gills. Some of these at least are endothelial in origin, as 

 they can be seen in the cells lining the sinuses. They may 

 represent abnormal amitosis. Many mitotic figures can be seen 

 in the spleen of this animal, although they are fewer than when 

 carmine was injected. The splenic cells proper are not par- 

 ticularly abnormal in appearance, although a few have hypo- 

 chromatic nuclei. 



