VALUE OF THE ATTRACTION-SPHERE. 155 



appearances of radiation round a point in the eggs of certain 

 jelly-fish (geryonidse) as being worthy of remark : " Setzen 

 wir aber gerade in diesem Augenblicke etwas Essigsaure 

 hinzu, so kommt der Rest, gleichsam, nur eine Andeutung 

 des friiheren Kernes wieder zum Vorschein. Auf beiden 

 Seiten dieser Kerniiberbleibsel zeigen sich zwei Protoplas- 

 maanhaufungen, deren dicht angesammelten Kornchen 

 zwei regelmassige sternformige Figuren darstellen. Die 

 Strahlen dieser Sterne werden durch die in geraden Linien 

 aneinander orerichten Korchen gebildet. Mehrere solchen 

 Linien reichen von einem Stern oder Anziehungscentrum 

 in einem Bogem zum andern, inden sie die Reste des 

 Keimblaschens umfassen. Das ofanze Bild ist ausserst klar 

 und deutlich und errinnert lebhaft an die Art und Weise 

 wie ausgestreuter Eisenstaub sich um die beiden Pole eines 

 Magneten anordnet. An den Randen gehen die Strahlen 

 allmahlig einerseits in das dlinnere Protoplasmantze des 

 Endoplasmas, andererseits in das dichte Ectoplasm liber." 



For a long time the existence of these appearances 

 attracted little more than desultory comment, and it was 

 not until fourteen years had passed in the gradual improve- 

 ment of our methods of research, that the classical publica- 

 tion of van Beneden (7) revolutionised our cytological con- 

 ceptions by showing that similar radial appearances were of 

 prime importance in the early ontogenetic development of 

 Ascaris and were probably to be regarded as cellular con- 

 stituents of the highest rank. Not content, however, with 

 merely demonstrating the existence and functional import- 

 ance of his " spheres-attractives," the Belgian naturalist 

 conferred upon them the title of " Organs of the cell," each 

 in itself composed of several parts. For if eggs be killed 

 and stained by the admirable, if somewhat heroic, method 

 he adopted, the spheres present a conspicuous three- 

 zoned appearance, caused by the presence of a central 

 body, surrounded by a light space, and enclosed on 

 the outside by a broad band of granular protoplasm. Under 

 the adopted treatment the central body stains bright 

 green, a little darker than the rest of the sphere, but it 

 is not in the least distinct in staining capacity from numer- 



