36 SEGMENTATION AND FORMATION OP THE LATEES. 



the nucleus is the spongework ; while on the other hand the 

 facts about the male and female pronuclei described on p. 33 

 are in favour of the second view, viz. that the deeply-staining 

 matter is the all important part of the nucleus. For in the 

 latter cases we have a stage in which the nucleus is represented 

 only by a mass of deeply-staining matter, which subsequently 

 enters into a more complicated relation with the surrounding 

 reticulum in order to give rise to the vesicular form of nucleus 

 ordinarily found. 



It is, therefore, impossible to decide which, if either, of these 

 two views is correct. Indeed, it seems useless to discuss the 

 matter except in connection with the functions of the nucleus. 

 The nucleus appears to be a kind of co-ordinating centre for a 

 given mass of protoplasm, and as such it may be looked upon 

 as a centre from which force emanates. If this is so, need it 

 have any essential structure beyond being the point to which 

 all the strings of the protoplasmic spongework converge — in 

 other words, such a structure as that possessed by the two poles 

 of the spindle in PI. Ill, fig. 11 ? Is it not conceivable that 

 a centre of this kind is necessary to the well-being of all 

 masses of protoplasm beyond a certain size ; and that if they do 

 not derive such a centre from a pre-existing centre they acquire 

 one de novo? May not the complexity of structure which 

 the nucleus ordinarily presents be a secondary feature, and 

 indicative of a higher organization of the protoplasmic mass 

 containing it ? Or, to put the matter in another way, is the 

 complicated structure of the nucleus as ordinarily seen the 

 cause or the result of the peculiar properties of the nucleus ? 



Without venturing to put forward any hypothesis on this 

 difficult and obscure matter, I may draw attention to a fact 

 which favours the view that the nucleus of any protoplasmic 

 mass is primarily a central and complicated nodal point to 

 which the strands of the spongework mainly converge, and that 

 the more complicated and apparently vesicular structure which 

 it generally presents is a secondary feature. The fact I refer 

 to is this : the first products of the division of the nucleus, 

 i. e. the earliest stage of the two new nuclei — I mean the poles 



