480 HOPE HIBBAED 



be the entire explanation of the matter. These masses are actual 

 precipitations of material in the normal cell, for in later stages 

 these fixing fluids do not form such precipitations. Figures 

 7 to 11 show that the bodies have become fewer as development 

 has proceeded. By the time the first division is well under way 

 all the large masses have disappeared and there is no indication 

 of the larger spaces in which they lay. They do not again reap- 

 pear after the first division. 



Similar precipitated masses may be found following other 

 methods of fixation, but the precipitations do not actively take up 

 any of the stains employed; they are always like the diffusely 

 stained ground cytoplasm. Figures 13, 14, and 15 illustrate 

 their appearance following modified Bouin fixation. In these 

 eggs, stained in alizarin and crystal violet, they were of the pale 

 pink color of the great mass of cytoplasm, and therefore not so 

 conspicuous as when stained in iron hematoxylin after picro- 

 acetic or sublimate-acetic fixation. In some eggs they looked 

 almost like bacteria, but they failed to stain with Ziehl's 

 carbol-fuchsin. Also their behavior in later stages could not 

 be accounted for if they were bacteria. 



As to the nature of these bodies, nothing is known beyond 

 the fact that they are precipitations of colloidal material in the 

 cytoplasm. It is probable that these bodies are of the same 

 character as the rods observed by Tennent ('20) in the egg of 

 Arbacia fertilized by Moira sperm, after fixation in sublimate- 

 acetic. 



In the unfertilized egg there is no uniformity in the orientation 

 of the precipitated masses, but as soon as the spindle for the 

 first division begins to form, they begin to be oriented parallel 

 to the astral radiations extending through the cytoplasm. They 

 appear as if swept about by the currents of more fluid protoplasm 

 flowing in toward the focus of the aster, until they present the 

 least surface in opposition to the direction of flow. Such a 

 flowing in of more fluid protoplasm to the centers of the hyaline 

 areas (such as are shown in figure 10) as the protoplasm goes into 

 a state of gelation at division, was demonstrated by Chambers 

 ('19). In this connection, Bowen's observations on the division 



