REACTION OF SELACHII TO INJECTIONS 107 



hours. Autopsy was performed eight hours after the first injec- 

 tion. The Prussian-blue reaction was obtained from the serum 

 and urine, but not from the bile, or stomach and spiral-valve 

 contents. Pieces of organs were fixed in 20 per cent formal- 

 dehyde acidified to 1 per cent with hydrochloric acid. 



4. An adult (Acanthias) received four hourly injections of 6 

 cc. each of Weed's solution, and was autopsied four and a half 

 hours after the first dose. Organs were fixed in absolute alcohol 

 acidified as above. 



5. An adult (Acanthias) received three injections of 9 cc. 

 each of Weed's solution at hour intervals and was autopsied 

 forty-five minutes after the last injection, , Forty per cent for- 

 maldehyde acidified to 1 per cent was used as a fixative. Mi- 

 croscopic examinations were made of various organs from the 

 animals, '3/ '4/ and '5' with the following results: 



a. Digitiform gland. In all the specimens examined there is a 

 central, distinctly blue zone, the width of about one-half the 

 radius of the gland as seen in transverse sections. Microscopi- 

 cally, the blue granules are seen almost entirely within the 

 blood-vessels, although a very few are found in the cells of the 

 tubules, but none in the lumen. The granules are present in the 

 capillaries and central venous sinuses in greater concentration 

 than in the vessels of any other organ. 



h. Kidney. The gross specimens are dark blue in color. 

 Sections show many Prussian-blue granules in the blood-vessels 

 and tubules. A very few only are present in the glomerular 

 cavities. They are found in the cytoplasm of both the secretory 

 and excretory tubules. Blue granules are found also in the con- 

 nective tissue of the kidney. 



c. Liver. The gross specimens are all light blue in color. In 

 a few hepatic cells blue granules are seen and they are present 

 in greater number in the ducts. This indicates either that the 

 solution passed directly into the ducts, as was thought to be the 

 case of trypan blue in bony fishes (Wislocki, '17), or else that the 

 solution passed through the epithelium quickly and out of the 

 ducts more slowly, thus becoming concentrated in the ducts. 

 In the liver of animal '3' the endothelium and the leucocytes of 



