1898] 'NUCLEAR REDUCTION' 119 



generation from which, after it had attained sexual differentiation, 



offspring was developed having a double number of chromosomes . . . 

 it is the re-appearance of the primitive number of chromo- 

 somes as it existed in the nuclei of the generation in which 

 sexual differentiation [rather cell-fusion, for whether it be 

 sexual or isogamous makes no difference to the point] first took 

 place." If we are to take literally the phrases that I have spaced, 

 we shall have to assume that two such plants as the onion and 

 the turban-lily have independently developed a pairing process ; for 

 the number of the nuclear segments is 8 and 1G in the former, 12 

 and 24 in the latter; the same would apply to the two forms of the 

 roundworm of the horse, with 2 (4) and 1 (2) segments respec- 

 tively — which is absurd. Yet so much of the essay is taken up in 

 proving that asexual reproduction is the older mode, not only in 

 primitive organisms, but in individual Orders of higher organisms 

 that one wonders if Strasburger has not really missed the incon- 

 ceivability of his statement as it stands ; and hence I cannot accord 

 to the explanation above-given the full weight of his distinguished 

 authority, as I should wish to do. 



Now we have seen that the process of 'nuclear reduction,' despite 

 its name, involves no necessary reduction in the quantity of nuclear 

 matter, but only in the number of the segments into which it is 

 distributed. Hence the process cannot have the physiological 

 function ascribed to it as a ' preparation for gamogenesis ' ; and, 

 since we have noted its occurrence at the inception of a long 

 series of cell-multiplications, this physiological function would be 

 absolutely useless. 



II 



A word about the functions of the chromatin or nuclein in 

 nuclear division. The amount of chromatin in a nucleus is 

 constantly changing ; very often after a cell is formed the nuclein 

 is much reduced in amount, and with this reduced amount the 

 cell does all its individual life-work. At the approach, how- 

 ever, of cell-division, the nuclein grows, and reaches a maximum 

 at the commencement of the nuclear division that precedes that 

 of the cell as a whole ; the nucleus of the daughter-cell repeats 

 the conduct of its parent. Whatever be the function of the 

 chromatin in the 'working' cell, as we may term it, it is 

 evidently less important than its function in the dividing 

 cell. The achromatic substance of the nucleus (limn) forms 

 the basis, as it were, of the nuclear segments, the strands on 

 which the chromatin is imbedded in the form of granules, like 

 the string of a necklace, or better, the braid in beaded passe- 

 menterie ; these granules first split, and then the threads on which 



