Smithsonian Report, 1896. 



Plate XV. 



Gill Filament of Necturus 



;># 



**.*- 



*s* 



i w 



/k Leucocytes . Emigrating 



Processes of Life Revealed by the Microscope. 



Fig. 5. These figures represent various steps in the removal of foreign matter from the 

 blood of Necturus. 



Gill filament of Necturus. — Part of a single gill filament greatly magnified to show the blood 

 vessels containing the red-blood corpuscles ij- be} and the leucocytes (?) or white-blood cor 

 puscles. The black dots (c) within the blood vessels represent carbon 1 articles which had 

 been injected into the veins. In many of the leucocytes are several carbon particles; there 

 are also several shown free in the blood plasma, g t, The tissue of the gill filament between 

 the blood vessels. 



Leucocytes emigrating. — This, the lower figure, represents a section of the skin with its cov- 

 ering, epithelium (ep>, and the corium (cor) or true skin. The leucocytes containing carbon 

 particles (c) are seen in the corium and penetrating the epithelium and finally free outside the 

 epithelium. The arrows indicate that the leucocytes emigrate from the body through the 

 corium and the epithelium, and finally into the space outside the epithelium. 



