670 INTERNAL SECRETIONS AND PRESERVATION OP LIFE. 



each. And yet the nucleus alone seems to be supplied with 

 such a membrane, while the surface of the cell is not. Indeed, 

 a prominent feature of these cells is the fact that their proto- 

 plasmic exterior is absolutely bare. 



After a .study of the characteristics of the granules, Gul- 

 land writes: "The granules of leucocytes are therefore not 

 products of the metabolic activity of the cell imbedded in a 

 structureless protoplasm, as Was hitherto supposed, but represent 

 an altered condition of the microsomes [the granules]. They 

 always form part of the cytomitoma [the net-work of fibers] 

 and are therefore plasmatic, and not paraplastic. They are 

 probably concerned with amoeboid movement, and they and the 

 rest of the mitoma are more visible the more active the cell." 

 Granules, as the plate distinctly shows, are plentiful within the 

 nucleus, and in the cellular substance likewise; indeed, in the 

 latter they are crowded around the centrosphere, the deepest 

 portion of the cell. 



If the granules are plasmatic, i.e., formed by substances 

 derived from the plasma, how does the latter reach the minute 

 areas in which the granules are formed? Channels seem to us 

 absolutely necessary for the passage of the blood-plasma, its 

 alkaline phosphates, and other plasmatic salts from which the 

 granules are formed. 



The prevailing view that the threads (mitoma) are con- 

 cerned with the amoeboid movements of leucocytes, as also in- 

 ferred by Gulland, is by no means, it seems to us, incompatible 

 with the possibility of their being plasma-channels, or efferent 

 canaliculi. Indeed, their elasticity does not eliminate the pos- 

 sibility of their being tubular, while their extension and re- 

 traction may, as in the sweat-glands, afford the mechanical 

 elements of an expulsive process. "It is certainly interesting 

 to note that, the more active the cells of this series become," 

 writes Gulland, referring to the acidophile (phagocytic) leuco- 

 cytes, "the more visible become their mitoma and the micro- 

 somes which form part of it. The lymphocytes in which no 

 mitoma can be seen are practically non-amoeboid. The hyaline 

 cells in which it is not very evident move but sluggishly. The 

 oxyphile cells, with a well-marked mitoma and microsomes, 

 move more rapidly, and the eosinophile cells, whose mitoma 



