218 MARGARET R. MURRAY. 



the nuclei in these stages, as well as in the C stage, are very 

 much elongated and distinctly constricted, and contain two or 

 sometimes more nucleoli (Figs, i, 2, 4); but this elongation, 

 when found in the B or C follicles, is always in a plane perpen- 

 dicular to the surface of the follicle, so that the constriction if 

 completed would divide the follicle into two layers, one beneath 

 the other. In no follicle has such a state of delamination been 

 observed; but when the follicle is approaching the A stage, 

 many of the nuclei appear to have oriented themselves so that 

 their axis of elongation is parallel to the follicular surface. 

 Nuclei which are apparently in transition from one position to 

 the other may be seen rather frequently (Fig. 8). Coincident 

 with this shift in the position of the nucleus, a change in the 

 shape of the follicle cell from a columnar to a squamous form 

 takes place; so that from being elongated like the nucleus in a 

 plane perpendicular to the follicular surface, the cell becomes 

 expanded and flattened in a plane parallel to that surface, 

 growing in absolute volume the while. This fact seems to 

 account for an enormous increase in the surface area of the follicle 

 as a whole, between the B and the A stages (occupying from 

 one to two months), without cell division. The results of the 

 tissue cultures indicate that the elongation and constriction of 

 the nucleus and the division of the nucleolus is at most an 

 extremely slow process. (Conklin, '03, suggests that frequent 

 division takes place between the D and B stages, and that 

 division is very slow in the A stage.) 



B. METAPLASMIC INCLUSIONS OF FOLLICLE CELL AND EGG. 



i . Distal Droplets. 



Unstained follicle cells in culture, used as controls, show 

 compact and very highly refractive nucleoli, somewhat less 

 refractive chromatin particles, and slightly refractive nuclear 

 strands. The cytoplasm has a rather homogeneous and finely 

 granular appearance, except for a number of large and exceedingly 

 refractive granules which are usually present and, whenever 

 found, appear in the part of the cell distal to the nucleus (Figs. 

 7, 8, 13). There is some, not a great deal, of variation from 

 cell to cell in the numbers of these droplets, but in general they 



