226 
INFLUENCE OF CLIMATE ON PLANTS AND ANIMALS. 
of different species, not varieties. When we trace the changes in a species of maple, as it 
approaches the confines of a temperate region, we may estimate the extent of change which is 
induced by climate. We can not compare dissimilar species with those which grow in the 
south, and say that their differences arise from the influence of climate, because those differences 
are specific—they should be different ; and they may be greener, straighter and taller, because 
those characters belong to them. But climate has influences, but not the influences in kind 
by which permanent changes are continued and propagated by the usual modes by which in¬ 
dividuals are multiplied, as by cuttings, grafting, layers or budding. Take off the pressure of 
a cold climate and the plant, which has been pinched and shrivelled, or dwarfed, will mount 
upwards, and spread itself under a genial sun. It is probable that climate favors the develop¬ 
ment of certain varieties more than others; indeed, there can be no doubt of the fact that va¬ 
rieties reach a higher state of perfection in certain climates than in others. If we study the habits 
of certain fruits, we shall find, and it is a fact well known, that they are very inferior, and even 
valueless in some climates. The plum is fine and very perfect along the Hudson river, but a few 
miles distant from it, it becomes inferior in quality. While, however, it is sufficiently manifest 
that varieties do not originate under the forces incident to climate, it is still difficult to point to 
causes which are directly operative in their production : it is, however, probable that a parental 
influence, those influences perhaps which are implanted for wise purposes, are effective in their 
development. Those species which are represented under numerous varieties, as the fruits and 
domesticated animals, have implanted in them a susceptibility to undergo those changes in their 
constitutions—it is in fact a part of their specific character; it is of a higher grade in some of 
the domesticated animals than others, and it is incident to those animals only which can be 
domesticated ; and those which are easily domesticated have the power of multiplying varieties 
in the greatest numbers, and display the widest differences in the extremes. These views ap¬ 
ply to man, who is more susceptible of change in his physical nature than any of the domesti¬ 
cated animals. Designed by the Creator to multiply and fill the whole earth, we find that his 
constitution is adapted to that end, to occupy all climates and adapt himself to a scorching sun 
or the frosts of a polar sky. Viewed in the extremes, the varieties in their physical characters 
present differences which are very striking; viewed however in their intellectual and moral 
aspects, the characters are those of a unity. Their power of speech and language, the con¬ 
veyance of ideas by speech, is universal: this oneness of mind, which displays itself all over 
the world, the religious sentiment which is universal, point with significance to the singleness 
of the species. It must be so, or else man is an anomaly in creation. Those who have en¬ 
tertained the theory of a plurality of species, which in their aggregate, compose the human 
race, rely wholly upon physical characters to sustain their views. Considered even in this 
light, are the differences in the race so great that they would not have originated in the pro¬ 
gress of time I Are the differences greatear than in the breed of dogs and other domestic ani¬ 
mals, which naturalists admit are of but one species 1 In all cases those differences are exter¬ 
nal ; they belong almost solely to the skin. If the bony skeleton is examined there are some 
differences it is true, in their proportions, but those differences are found in each of the races, 
