408 TRANSACTIONS AND PROCEEDINGS OF [Sess. lvi. 



small fragments. Gradually, however, nourishment becoming 

 more plentiful, the rate at which cytoplasm was formed 

 became greater than the rate by which it was transformed 

 into chromatin, and this resulted of necessity in an accumula- 

 tion of cytoplasm round the nucleus, or as the author puts 

 it, in the production of a "cytoplasmic field." This cyto- 

 plasmic field allowed the nucleus a larger area to exhibit its 

 activity, and as a result karyokinesis was ultimately developed, 

 as the most elaborated form of nuclear division. 



Simultaneously with the production of a cytoplasmic field, 

 the habit of cells to adhere to one another after division 

 arose, and thus unicellular organisms became multicellular. 

 Also synchronously with the development of a cytoplasmic 

 field, sex originated. For individuals differentiated into 

 nucleoplasm and cytoplasm attained a large size, and sper- 

 matogonia [zoosporangia, G. M.] were developed, whose 

 function it was to give rise to a number of primitive flagel- 

 lated individuals or spermatozoa [zoos]3ores, G. M.]. Thus 

 far reproduction is still asexual ; but gradually some of these 

 spermatogonia in their turn assimilated food material to such 

 a degree and developed cytoplasm in such quantity, that their 

 nuclei (i.e., the chromatin) were incapable of governing the 

 cytoplasm. The spermatogonia, cast off the parent, were then 

 either unable to develop chromatin in a sufficient quantity to 

 allow the latter to govern the cytoplasm, and to divide it into 

 spermatozoa, when an ovum resulted, which, for its future 

 development, depended on an active and more primitive 

 spermatozoon bringing in new chromatin, or ; — a partheno- 

 genetic ovum resulted which was able to undergo further 

 development without the aid of fertilisation. 



It is therefore evident that, according to Eyder's view, 

 the " ovum " is nothing but a spermatogonium, i.e., a cell 

 which ought to give rise to a number of asexual flagellated 

 primitive individuals, but which lias lost this power due to 

 an excessive assimilation of food -material. That such an 

 ovum still attempts to give rise to spermatozoa seems to the 

 author an established fact, for he considers the formation of 

 polar bodies as an endeavour of tlie ovum to break up into 

 spermatozoa, and therefore the polar Ijodies as spermatozoa. 

 " Sexuality was then the outcome of the unequal growth of 

 germ cells of the same species, induced by tlie self-regulative 



