532 MATURATION AND IMPREGNATION OF THE OVUM. 



rod-like body, the free end of which is situated between the two 

 suns which occupy the prominence of the germinal vesicle. At 

 a slightly later period granules may be seen at the end of the 

 rod and finally the rod itself vanishes. After these changes 

 there may be demonstrated by the aid of reagents a spindle 

 between the two suns, which Hertwig believes to grow in size as 

 the last remnants of the germinal spot gradually vanish, and he 

 maintains, as before mentioned, that the spindle is formed at the 

 expense of the germinal spot. Without following Hertwig so 

 far as this 1 it may be permitted to suggest that his observations 

 tend to shew that the body noticed by Fol in the median line, 

 on the inner side of his spindle, is in reality a remnant of the 

 germinal spot and not, as Fol supposes, part of the germinal 

 vesicle. Considering how conflicting is the evidence before us 

 it seems necessary to leave open for the present the question as 

 to what parts of the germinal vesicle are concerned in forming 

 the first spindle. 



The spindle, however it be formed, has up to this time been 

 situated with its axis parallel to the surface of the egg, but not 

 long after the stage last described a spindle is found with one 

 end projecting into a protoplasmic prominence which makes its 

 appearance on the surface of the egg (Fig. 6). Hertwig believes 



FIG. 6. Portion of the ovum of Asterias glacialis, shewing the spindle formed from 

 the metamorphosed germinal vesicle projecting into a protoplasmic prominence 

 of the surface of the egg. Picric acid preparation (copied from Fol). 



that the spindle simply travels towards the surface, and while 

 doing so changes the direction of its axis. Fol finds, however, 

 that this is not the case, but that between the two conditions 



1 Hertwig's full account of his observations, with figures, in the 4th vol. of the 

 Morphologische Jahrbuch, has appeared since the above was written. The figures 

 given strongly support Hertwig's views. 





