Origin of Species Variorum

→ two thirds of 1859

two-thirds 1860 1861 1866 1869 1872

→ the trees now growing on the 1859

OMIT 1860 1861 1866 1869 1872

→ display 1859

which must formerly have been cleared of trees, now display 1860 1861 1866 1869 1872

→ between the several kinds of trees must here 1859 1860 1861 1866

must 1869 1872

extinct or very rare in England, the heartsease and red clover would become very rare, or wholly disappear. The number of humble-bees in any district depends in a great

measure

degree

on the number of field-mice, which destroy their combs and nests; and

Col.

Mr. H.

Newman, who has long attended to the habits of humble-bees, believes that "more than →two thirds of

of them

them

are thus destroyed all over England." Now the number of mice is largely dependent, as every one knows, on the number of cats; and

Col. Newman

Col.Newman

Mr. Newman

says, "Near villages and small towns I have found the nests of humble-bees more numerous than elsewhere, which I attribute to the

numbe

number

r of

cats that destroy the mice." Hence it is quite credible that the presence of a feline animal in large numbers in a district might determine, through the intervention first of mice and then of bees, the frequency of certain flowers in that district!

In the case of every species, many different checks, acting at different periods of life, and during different seasons or years, probably come into play; some one check or some few being generally the most

potent;

potent,

but all

concur

will concur

concurring

in determining the average number or even the existence of the species. In some cases it can be shown that widely-different checks act on the same species in different districts. When we look at the plants and bushes clothing an entangled bank, we are tempted to attribute their proportional numbers and kinds to what we call chance. But how false a view is this! Every one has heard that when an American forest is cut down, a very different vegetation springs up; but it has been observed that →the trees now growing on the ancient Indian

ruins

mounds,

in the Southern United States, →display the same beautiful diversity and proportion of kinds as in the surrounding virgin

forest.

forests.

What a struggle →between the several kinds of trees must here