410 TRANSACTIONS AND PROCEEDINGS OF [Sess. LVI. 



up into spermatozoa if they had not been overfed. Starting 

 with a non-sexual cell, or individuum, I believe it to have 

 the power of developing either male or female tendencies, 

 according to the facilities in acquiring and assimilating food. 



There is still another point in which 1 cannot agree with 

 Eyder, namely, that the chromatin of the nucleus is the 

 most highly developed constituent to the cell ; the researches 

 during the last few years all tend to show that the achromatin 

 is the really essential part of the cell, and I have to repeat 

 what I stated above, that in all probability those constitu- 

 ents of the chromatin segments of the nucleus which we are 

 in the habit of staining with the anilin dyes are only simple 

 albuminoid compounds on the road towards a transformation 

 into the achromatic elements of the cell, in other words, 

 that we are in reality not staining a constituent part of the 

 living cell, but only food particles contained in the achro- 

 matic mesh work of the nuclear and nucleolar organs of 

 assimilation. 



Hartog * defines a zygote as a cell resulting from the 

 fusion of gametes, and a gamete as a cell which fuses 

 with another, cytoplast with cytoplast, and nucleus with 

 nucleus. Gametes are believed to have arisen thus, p. 

 79 : — " Two distinct modes of fission occur in relation to the 

 growth of the organism in Protozoa and I'rotophytes ; in the 

 first, after each division the daughter-cells grow to the size 

 of the parent (more or less) before dividing in turn ; in the 

 second, the intervals of growth are suppressed, and a series 

 of successive fissions takes place, resulting in a brood of 

 small individuals (swarmers, zoospores, &c.). We call this 

 second type of fission ' brood-formation,' the resulting indi- 

 viduals ' brood-cells.' Necessary, like facultative, gametes 

 are essentially, in origin at least, modified brood-cells. 

 Hence, when the ancestral development is not lost, gametes 

 will always be produced by brood- formation, while tissue- 

 cells (except in the earlier embryonic state) are formed by 

 the first mode of fission." 



Given this origin of gametes, the author seeks to explain 

 the origin of binary sex, or, in other words, of maleness and 

 femaleness, ])y the phenomena of gamete- formation, as seen 



* M. Ilartog, Some I'lolil. of Reprod. &c., Quart. Jouru. Micr. Soc, vol. 

 xxxiii., part 1, Dec. 1891. 



