ITS CHEMICO-PHTSICAL AND MORPHOLOGICAL PROPERTIES 



corpuscle, two were present, lying 

 close together, either in the im- 

 mediate neighbourhood of the 

 resting nucleus, or in an indenta- 

 tion of it, directly in contact 

 with the nuclear membrane. As 

 a rule no radiation sphere was to 

 be seen in these cases ; some- 

 times the two central corpuscles, 

 instead of touching each other 

 closely, were somewhat separated 

 from one another, and under 

 these circumstances the first com- 

 mencement of a spindle formation 

 between them was visible. 



A 



FIG. 35. Pigment cell of the Pike, with 

 two nuclei, and one pole corpuscle, sur- 

 rounded by a radiation sphere. (After 

 Solger, Fig. 2.) 



Fia. 36. A Nucleus of an endothelial cell from the peritoneum of a Salamander laiva, 

 with the pole corpuscle lying near (after Flemming, Fig. 2). B Nucleus of a cou- 

 nective tissue cell from the peritoneum of a Salamander larva, with the pole corpuscle lying 

 near (after Flemming, Fig. 4). 



Van Beneden (II. 52) first advanced the theory that the central 

 corpuscle, like the nucleus, is a constant organ of each cell, and that it 

 must be present in the cell in some portion of the protoplasm near 

 the nucleus. The property possessed by the central corpuscle of 

 being able to multiply itself by spontaneous division (vide Chap. 

 VI.) seems to be in support of the first part of this view, as is also 

 the role it plays in the process of fertilisation (vide Chap. VII. 1) ; 

 but the second portion of this theory, although it is very generally 

 accepted, that the central corpuscle belongs to the protoplasm, 

 appears to me, on the contrary, less certainly true. 



