THE SELF-FERTILISATION OF PLANTS. 1 1 
Mr. Darwin did not cultivate any other plants sufficiently 
long to enable one to test the results of the permanency of the 
effects of crossing ; but what I wish to point out is that 
we must not confound permanent morphological characters 
obtained by crossing with any physiological benefit necessarily 
and much less permanently resulting from it. Mr. A. Knight’s 
varieties of peas obtained by crossing may have retained their 
morphological characters by which they were known in the mar- 
ket for sixty or more years ; but to imagine that their longevity 
was due to the fact of crossing, is an assumption based upon no 
proof whatever. Mr. Darwin’s experiments appear to me to 
prove the exact contrary, for in no case does he show that the 
physiological effects are more than transitory, even when the 
offspring are fresh crossed every year ; while, on the other hand, 
Mr. Knight’s peas were actually propagated for sixty years by 
self-fertilisation alone. 
The reader will now ask, “ What, then, is the good of cross- 
ing at all?” I reply, as far as the sole object of plant-life is 
concerned — that is, an abundance of seed — that the species may 
survive in the struggle for life, there is no good at all , and that 
self-fertilisation is the best and most certain method. And if 
it be asked why there are so many adaptations to insects, I 
reply that I believe it was an inevitable response to the irrita- 
tion caused by the insects themselves. Moreover, insects often 
do more harm than good, when they discover that they can 
secure the honey by illegitimately perforating the corolla tube 
from without. 
I believe that plants would never have had conspicuous peri- 
anths at all if insects had not visited them ; but by causing a 
continual flow of nutrition to the external whorls, in consequence 
of their sucking away the juices, hypertrophy has set in, and 
the result is that Man , but not the plant, has gained the benefit, 
for he can appreciate the innumerable beautiful forms, colours, 
and scents, which so many flowers now possess. This result, how- 
ever, is occasionally at a sacrifice to the r plant itself , in that it has 
in some cases, but in the minority, lost the power of self-fertilisa- 
tion ; and, consequently, if a plant be an annual or biennial, and 
be not visited, it must succumb in the struggle for life, and so 
perish altogether. Self-fertilising plants are mostly annuals 
and small ; both features being of great advantage in maintaining 
their continued existence. The rapidity of maturation and 
shedding of seed is perfectly astounding, generation after 
generation being produced in a few weeks, while the absolute 
amount of seeds produced is quite incalculable. 
Lastly, the self-fertilised plants are the only ones, as a rifle, 
which are cosmopolitan. I must refer the reader to my paper 
in the “ Linnaean Transactions ” for detailed lists of localities 
