VALUE OF THE ATTRACTION-SPHERE. 323 



ment, however, is absolutely independent of the archo- 

 plasmic structure, which degenerates, and during the later 

 phases of mitosis vanishes in the cytoplasm altogether. 

 The new archoplasms which arise in the daughter cells, as 

 a coalescence of these cyto- and nucleo-plasmic spindle 

 fibres, are therefore to be regarded as nothing but temporary 

 modifications of the nuclear and cytoplasmic substances, and 

 of an entirely non-persistent nature. 



It will be seen that the simple radiation which spreads 

 from the centrosomes in these dismembered spheres, gives 

 to the former bodies exactly the appearance they possess 

 in the tissue (somatic) cells whose spheres are of the simple 

 tvpe ; while the concomitant presence of a functionless 

 archoplasm converts the ensemble of cell structures into 

 a form, with spheres intermediate between the simple and 

 the compound types, such as we have been seeking, for it is 

 scarcely possible to doubt that the simple radiation here 

 present round the centrosomes (Fig. II.) is similar to that 

 of simple spheres (Fig. III.). Nor can we resist the further 

 inference that this radiation stands also for what would be 

 an external envelope, were the centrosomes to enter into 

 the archoplasm ic substance. 



From all this it would appear, then, that the radiation 

 of a simple sphere (Fig. III. e) is really equal to the 

 external radial envelope of the compound or reproductive 

 type (Fig. I. e), and that in the former the archoplasmic 

 constituent has become (gradually ?) suppressed and is now 

 completely wanting. The facts, however, may be recapitu- 

 lated as follows. 



In the first (compound and probably primitive) type 

 of sphere, the archoplasm persists, being alternately 

 stretched out into a spindle figure and then in part re- 

 condensed in each succeeding generation. In the second it 

 is not persistent, because, although it arises as a coalescence 

 of the spindle fibres, owing to the extra-archoplasmic 

 position of the centrosomes, it is not reconstructed into a 

 spindle and degenerates in the cell. While in the third or 

 simple type, the spindle fibres do not coalesce to form an 

 archoplasm at all. 



