T H E 
NEW PHYTOIiOGIST. 
Vol. XVII, Nos. 8 & 9. Oct. & Nov., 1918. 
[Published November 14th, 1918.] 
ON THE NATURE OP FERTILIZATION AND SEX. 
By W. Neilson Jones, M.A. 
[Lecturer in Botany , Bedford College.) 
HE essential fact in the process of fertilization is that a 
A male gamete fuses with a female gamete to produce the 
zygote. This fusion is probably the result of a definite chemical 
attraction, and in some cases the chemical nature of the attracting 
substance would appear to have been identified. 
Thus, in the ferns, malic acid has been credited with this 
role, and the attraction of the motile spermatozoids to the 
archegonia and egg-cells has been imitated by filling a small 
capillary tube, closed at one end, with malic acid and dipping 
the open end of the tube into a drop of water containing the 
spermatozoids. 
Another characteristic of the phenomenon of fertilization is 
that the egg-cell, containing an abundant store of nutriment, is 
inert until fusion with the male gamete occurs, whereupon rapid 
cell division at once ensues. 
Sexual reproduction in general is evidently closely correlated 
with nutrition, and appears to be in some measure a starvation 
phenomenon. This may be recognised in its simplest form among 
unicellular organisms. In the case of the free-swimming unicel¬ 
lular alga Chlamydomonas, individuals which normally, in the 
vegetative state, lead independent lives, under starvation conditions 
develop a mutual hunger and fuse in paiis, 01 , accoiding to the 
species, exhibit various degrees of sex differentiation, expressed by 
the relative activity and passivity of the fusing cells. 
These phenomena of fertilization appear to the writer to be 
not peculiar to fertilization, but to be of the same kind as those 
which characterise parasitism, symbiosis and the reactions of living 
protoplasm in general. 
