46 BOTANICAL GAZETTE ,- [july 



lightly with most other stains. The staining reactions make it 

 improbable that they are starch or chromatic material or any of the 

 more usual constituents of cells. They are probably some sort of 

 stored-food material, since they disappear slowly at a later stage, 



■ 



when such stored foods are being used. They appear in all stages 

 following this up to about that shown in fig. 2j. Their number and 

 size in different cells varies greatly, in some being absent. Some 

 of them are shown in figs. 11-21. They are usually much more 

 numerous than shown in the figures, which show only those visible 

 in a single optical focus, or even fewxr than that in figs, iy-20. They 

 often line up along the central region of the spindle of the first divi- 



M 



sion, or along the subsequent wall (when one forms) in such masses 

 as to obscure the details of cell structure entirely in that region. The 

 cytoplasm itself grows denser and denser as the time of division 

 approaches; fig. 11 shows it at about its maximum. Figs. 11 and 13 

 show two different aspects of the cytoplasm of dividing cells, the for- 

 mer being the common one. The beaded threads shown in fig. 12 

 are very characteristic of the cytoplasm of the cells during maiosis. 



Thc spindle originates as a weft of kinoplasmic fibers around the 

 nucleus. The fibers then form a number of poles such as those 

 shown in fig. 11. Three of these poles become prominent and the 

 others disappear. The tripolar stage passes into the bipolar by the 

 further elongation of two poles and the breaking-up of the third 

 {fig. 12). Fig. I J presents a surface view of the mature, sharply 

 pointed, bipolar spindle. The chromatic mass (simplified in the figure) 

 proved too dense and the chromosomes too small and numerous to 

 make any trustworthy observations on the method of chromosome 

 splitting. The chromosomes usually pass to the poles in a more or 

 less straggling manner, though sometimes they advance in regular 

 lines. Reaching the poles they may or may not organize a resting 

 nucleus; wheti the second division follows very soon they probably 

 do not. Fig. 14 shows the beginning of the formation of the resting 

 network before the spindle has disappeared. Fig. 15 shows the 

 chromosomes still free after the formation of a w^all between the 

 daughter nuclei. In fig. 16, from which the spindle fibers have not 

 entirely vanished, the daughter nuclei arc in the resting condition. 



After the first division, a wall may (figs. 15^ i6j lOy 20) or may 



