530 BULLETIN OF THE 



moval from the area, and thi-s motion is compensated by a corresponding 

 (centripetal) movement of the granular protoplasm. The same, it is true, 

 could not be claimed for the clear rays, for their place is subsequently 

 occupied by granules which it is fair to presume were simply displaced 

 during the astral manifestation, since the granulation of the yolk is not 

 permanently diminished by their formation. 



I do not claim that there is absolutely no transfer of substance to and 

 from the centres of attraction, — on the contrary, I believe the phenomena 

 are, on any other assumption, unintelligible ; but it seems to me that 

 the formation of a clear area and the existence of radial striations are far 

 from commensurate, and that to claim that the rays are only the optical 

 expression of currents is to associate as cause and effect two things which 

 have not necessarily any such connection with each other. 



The view suggested by Strasburger, that the rays are evidence of the 

 polarity of the protoplasmic molecules, seems to imply that the astral con- 

 dition is effected by the molecules having the direction of their principal 

 axes so altered as to be radial, — that is, practically parallel to each 

 other, — this position being maintained by the (attractive V) influence 

 emanating from the so-called centres. But the spiral asters (unless they 

 are superimposed conditions) appear unexplainable upon this hypothesis, 

 since the direction of the force must always be strictly radial, and the 

 attracted molecules could assume all intermediate attitudes between the 

 radial and nearly tangential only by the intervention of other forces, of 

 the existence of which we have no other evidence. If the rays are due 

 to the polarity of the molecules, their position must be very unstable, 

 and it will exist only so long as the attractive force continues to be 

 exerted. In hardened specimens the force is of course interrupted, and 

 the astral conditions are preserved only in virtue of being fixed by the 

 reagent before the latter had interrupted the processes generating the 

 supposed force. The intensity of the attraction (or repulsion) must of 

 necessity diminish with the distance ; but does that warrant the lapse of 

 such an interval as occurs between the time when the central mole- 

 cules respond to the force and that when those near the periphery give 

 evidence of a like condition % But, further, I do not understand how 

 such an orientation of all the molecules could accomplish a difference 

 in the refractive properties of neighboring rays of the protoplasm. It 

 would not be claimed that the molecules are directly visible, or that 

 their alignment was capable of direct observation. The protoplasm 

 would still remain homogeneous. 



BUtschli's opinion, that the asters are the optical expression of a 



