﻿412 BO TANICAL GAZE TTE [jUNE 



spindle formation. This spindle is intranuclear, thus agreeing 

 with the nuclei of fungi generally. However, it is usual in the 

 intranuclear formation of the spindle for the poles to originate 

 in contact with the nuclear membrane, whereas in this case they 

 are far from being so placed. As to the exact mode of spindle 

 formation we can say nothing further than that the threads of the 

 spirem group form themselves into a spindle. No centro- 

 somes or polar radiations were distinguished in any stages of 

 the mitosis. 



During progress from the condition shown in fig, J to that 

 oi fig, 10 J a striking and remarkable change has occurred, in that 

 the whole chromatin content has decreased largely. Figs. 12 

 and 14 show a still greater reduction. All of the chromatin- 

 bearing parts diminish, until, as in fig, 11, only a well marked 

 spindle remains, bearing a few short chromosomes. In all early 

 stages there seems to be a vast quantity of chromatin distributed 

 at first throughout these globules, and later {^fig. 7) on a linin net- 

 work of large extent, while after the formation of the spindle 

 the chromatin is insignificant in amount. There is here either a 

 great condensation or an actual reduction in the amount of 

 chromatin. Increase in the density of staining favors the former 

 view, although the decrease in volume is too great to be attrib- 

 uted wholly to such a cause. 



The nuclear membrane is gelatinized as early as the condi- 

 tions shown in figs, 5 and 6. With the constant shrinkage of 

 the nucleus it decreases in superficial area, but apparently not in 

 volume, inasmuch as it constantly grows in thickness. Eventu- 

 ally the spindle, by the constant shrinkage of the gelatinous 

 membrane, comes to lie in a narrow court surrounded by abroad 

 dense zone of granular substance staining strongly with the 

 orange G, This halo, clearly the residue of the altered nuclear 

 membrane, is a conspicuous object in the field, though the 

 nucleus itself is now very small, averaging 10 /i or less in length. 

 The nucleolus persists unchanged in character from the condi- 

 tion shown in fig, 10, i, e., it is similar to the nuclear vacuole 

 shown '^^fig^J^ 



A distinct view, slightly after metaphase, is given in fig- ^^r 



