248 PROTOPLASM 



course the modification of our former conception of the stria- 

 tion, inasmuch as we have to seek in the central bodies those 

 structures which by their action on the protoplasm produce 

 the formation of the asters. According to our view, how- 

 ever, this action consists in the fact, that the centrosome 

 attracts the matters dissolved in the enchylema, or the 

 enchylema itself partly, as the case may be, in the same 

 way as a hygroscopic substance attracts water, and that the 

 diffusional migration set up in this way produces the 

 appearance of rays. That this view finds further support in 

 the facts, follows from the observations of Boveri, who 

 showed that in the case of Ascaris megalocephala the central 

 bodies, which are very small in the resting condition of the 

 cell, gradually increase to a considerable extent during the 

 formation of the asters, and diminish again in the same way 

 afterwards.^ This observation proves directly that the 

 central bodies take up matter from their surroundings, at 

 the expense of which they grow in size. This observation 

 therefore, as has been said, harmonises very well with the 

 theory proposed. There remains only the question, 

 whether we can also express any opinion upon the 

 clear central area of the suns, in which the central body 

 lies, the so-called attraction-spheres of van Beneden, or the 

 archoplasm of Boveri (periplast, Vejdowsky, 1888). This is 

 not possible directly. There is, however, a physical pheno- 



1 The investigations of Vejdowsky, so interesting in many respects, but in 

 my opinion not quite continuous, and therefore in part erroneously inter- 

 preted, upon the process of segmentation of the ovum of Rhynchelmis, seem 

 to prove a very considerable increase in the size of the central body during 

 the formation of the spindle. Since Vejdowsky probably overlooked the 

 central bodies, on account of their smallness, during the resting condition, he 

 interprets them as the forecasts of new attraction-spheres, his so-called "peri- 

 plasts," which arise, at least in the first cleavage cells, endogenously within 

 the pre-existing periplasts. From a comparison of his results with those of 

 van Beneden and Boveri, etc. , it may, as has been said, be safely concluded 

 that Vejdowsky is wrong in making the central body, observed in the 

 swollen condition, pass over into the later periplasts or attraction-spheres. 

 It seems to me not without interest that Vejdowsky figures stages in the 

 division of the central body which recall karyokinesis, and hence the opinion 

 given by me elsewhere (1891), that the central bodies may perhaps corre- 

 spond to the micronuclei, with karyokinetic division, of Infusoria, receives 

 a certain amount of support. 



