物种起源（英文全本）约15.1万字全本免费阅读-在线阅读无广告-(英)达尔文

of species

when

crossed

and of

their

hybrid

offspring.

It is

impossible

to study

the

several

memoirs

and works

of those

two

consci-

entious

and

admirable

observers,

K¨olreuter

and

Gartner,

who almost

devoted

their

lives to

this

subject,

without

being

deeply

impressed

with the

high gen-

erality of

some

degree of

sterility.

K¨olreuter

makes the

rule

universal;

but then

he cuts

the knot,

for in ten

cases in

which he