70 JOHNS HOPKINS UNIVERSITY MORPHOLOGICAL MONOGRAPHS. 



as though all the reticulum of the nucleus had been crowded together 

 at the surface. Judging from appearances like p (Fig. 20), the 

 hollowing out, so to speak, of these nuclei, would seem to be a 

 process of vacuolation, the reticulum becoming crowded aside to the 

 surface. But how, on this view, to account for the formation of the 

 axis, I do not know. Perhaps the axis is formed by a pushing in of 

 two opposite poles of a nucleus, the two invaginations meeting and 

 fusing. On this supposition one might expect the axis to be hollow 

 (cylindrical), but I could not determine that it was. Perhaps the 

 centrosphere (or spheres) (see the next paragraph) has something to 

 do with the formation of the axis (Fig. 20, b, g, e, etc.). 



In the nuclei of Fig. 20 with the dark outlines, and of Fig. 7 

 a small reticular body is seen just opposite one end of the axis, or 

 opposite both ends in g. In d (Fig. 20) this body is seen next the 

 axis just below (outside) the hollow cup represented by the hollow 

 ring. In this instance a central granule is seen in the reticular 

 body, as also in c. I take this reticular body to be the centrosphere, 

 and the central granule in c and d the centrosome. In k, 1, m, n, 

 and o (Fig. 20), which are from another series, in which the walls 

 of the nuclei did not stain so dark as in the other nuclei of the 

 same figure, a nucleolus could be definitely seen, indeed, sometimes 

 quite perched upon the wall of the nucleus (k, 1). In several 

 instances I could see two nuclei, as in o. But besides these nucleoli, 

 I could in several instances see quite definitely a reticular body 

 (centrosphere) opposite the axis (m, n, o) quite as I described for the 

 nuclei with the dark outlines. In a, b, c, d, e and g the nuclei could 

 not be so readily demonstrated, but I could occasionally see a darker 

 stained body as in a, c and g, that I have no doubt is the nucleolus, 

 which here, again, is perched quite upon the surface of the nucleus. 

 This position of the nucleolus is perhaps due to its having been 

 crowded to one side by the nucleus becoming hollow. It is no 

 uncommon thing, either, to find several nuclei in a single cell, 

 sometimes in process of division or just divided as o and e (Fig. 20), 

 also h, i and j. The whole nuclear phenomenon that I have described 

 seems to be one of division. Perhaps it is somehow associated with 

 the giving off of the secretion of the cells, for these nuclei seem to 

 be found in greatest abundance in those cells in which the secretion 

 is most abundant. In Conant's sections I found but little evidence of 

 these nuclear phenomena as also little secretion, which all goes to 



