60 
FIRST CLASS OF THE VERTEBRATED ANIMALS. 
yielding fertile races, we have presumptive evidence that this supposed degeneration 
of species cannot have existed, and we derive from the known insufficiency of the 
present causes of change a positive ground for inferring their descent from distinct 
original types. The mere circumstance of our being able to induce by art and con- 
trivance a fertile union between two species, is not sufficient to counteract this evi- 
dence, when we see that these same species preserve themselves distinct in the wild 
state, and continually maintmn certain well-defined peculiarities. 
Pallas was led to infer that some of our domestic animals, such as the Sheep, the 
Goat, and the Dog, are factitious beings, not proceeding from any permanent origin, 
but from the union of several distinct species, such as the Dog from the Wolf, the 
Fox, and Jackal; the Sheep from the Moufion and Siberian Argali; and the common 
Goat from the Persian and Caucasian Goats with the Ibex. Wo know that these 
inimals have given rise to fertile hybrids ; and hence it becomes impossible to say 
now far their varieties may be owing to foreign contamination, or to the occur- 
rence of connate varieties in the original species. It is, however, useless to indulge 
in conjecture where data arc defective; but from analogy we might infer that a very 
small part of their variolies have been owing to foreign admixture. 
It now remains for us to notice the theory of the successive Transition of 
Species proposed by M. Lamarck. According to him, the habits and manners of life 
assigned to each animal do not follow from any original form peculiar to its species: 
but that, on the contrary, the form of each species is the result of its habits, its 
manner of life, and other influential causes, which, in the course of time, have consti- 
tuted the shape of tlie body and the parts of the animal. W'ith new forms, new 
faculties have been acquired; and thus gradually Nature has produced the animals as 
we now see them. 
Wo must in justice remark, that this theory has been censured in this country with 
undue severity, from its appearing at first sight to dispense with the agency of a First 
Cause in the creation of the several species of animals. But in reality, a creative power 
is as indispensable in maintaining the successive transition of forms, as in originally 
creating them. Lamarck himself was well aware of this, for ho observes, “ When I 
see that Nature lias placed the source of all the actions of animals, of all their facul- 
ties, from the most simple to those which constitute instinct, industry, and finally 
reasoning — in their wants, which alone establish and direct their habits; ought I not 
to acknowledge in this power of Nature, that is to say, in the existing order of things, 
the execution of tlie will of its Sublime Author, who has imparted them the power?” 
As an illustration of this supposed transition of species, we shall show M. La- 
marck’s method of explaining upon his theory, how it comes to pass that some 
Mammalia can fly. A very ancient race of common Squirrels had long amused 
themselves with leaping from tree to tree, and thence had acquired a habit of extend- 
ing their bmbs like a parachute. From frequent repetitions of this act, the skin of 
their sides became gradually enlarged, in course of time, and a loose membrane ex- 
tending from the fore to the hind feet, embraced a large volume of air, and broke 
the force of their fall. In a word, they acquired tho characters of the Flying 
Squirrels (Pterorngs). These animals, however, were still without membranes 
between their fingers. 
But a race of .Squirrels of much higher antiquity, after undergoing the preceding 
metamorphosis, had acquired a habit of taking still longer leaps than the former. 
Accordingly the skin of their sides became more ample, uniting not only the fore and 
hind legs, but even the tail with the hinder foot, as well as the fingers with each 
other. These now form our Flying Lemurs ( Galeopithecus). 
There was, however, a third race of Squirrels vastly more ancient than any of these, 
which had contracted a habit, in the course of time, of extending not only their limbs, 
but also their fingers. From this habit, long preserved and become inveterate, they 
not only acquired lateral raemhers, but an extraordinary elongation of the fingers of 
the anterior limbs, with largo intermediate membranes, so that at length they con- 
stituted those singular wings wliich we find in the Bats ( Vespcrtilio). 
“ So great is the power of habit,” observes M. Lamarck, “ that it singularly 
aflbets oven the conformation of the corporeal parts, that it imparts to those ani- 
mals which have- contracted certain habits through a long course of ages, certain 
faculties which other animals of different habits do not enjoy.” 
Upon this theory, it was requisite that the higher orders of animals should be re- 
garded as of tho greatest antiquity, a longer time being necessary for their transition 
from those simple forma, which were supposed to have been first created. “ I have 
no doubt, proceeds Lamarck, “ that all the Mammalia have originally sprung from 
the ocean, ana that tho latter is the true cradle of the whole Animal Kingdom. In 
fact, we still see tliat the least perfect animals are not only the most iinmerons, but 
that they cither live solely in tho water, or in thuso very moist places, where Nature 
has performed, and continues to perform, undiir favorable circumstances, her direct 
or spontaneous generations; ami there, in the first place, she gives rise to the most 
simple animalcules, from which have proceeded all the animal creation." — (Philoso- 
phic Zoologique, tom. 2, p. 456). 
Wo -must remark, that there has never y«t been, within the historical era, a well 
authenticated fact of any animal of one species having acquired organs, or faculties 
belonging to another ; nor are any spetpos known to have lost any of their senses or 
pow'ers to make way for new ones. It must further be observed that, while we have 
never found any ef these transitions in circumstances within tho sphere of our 
investigations, Lamarck places them precisely in those, where they cannot be proved 
or disnroved by direct observation. MTicre did these transitions begin ? In 
the abysses of tho Ocean, where Man has never penetrated, and where myriads of 
beings lie concealed from his observation, perhaps for over. What animals owe 
their origin to spontaneous generation? Animalcules, a class of beings the most 
remote from our observation, and whose forms can only be traced through the de- 
ceptive medium of the microscope. When did these transitions occur? Before 
the historical era, in those remote and inaccessible ages, whose existence is alone 
attested by tho organic remains imbedded within the surface of the earth. 
But, observes Lamarck, “ there is a very good reason why we do not see those 
changes sucuessively performed, which, hare diversified the known animals, and brought 
them to their present state. We see them only when they are finished, and not when 
undergoing the change ; and we very naturally infer that they always have remained 
as we see them.” This is a prejudice. “ If the average duration in the life of each 
generation of Men were only a second, and if there bo a pendulum mounted and in 
motion, each generation wonld consider this pendulum really to be at rest, never 
having seen it change in tho course of their lives. The observations of thirty genera- 
tions would not demonstrate any thing positive concerning the vibrations of this 
instrument.” 
We may remark, that our sole means of judging of unknown olqects is by compar- 
ing them with others which are known, and that it is unphilosophical to found a theory 
of what occurs, or has occurred, in remote and inacee.ssiblo parts of the creation, in 
direct opposition to what is seen to happen within our own sphere of observation. 
Tho earth appears to be at rest, if it be compared with objects on its surface; and 
we reason correctly, for, in respect to them, it is at rest. But on referring it to 
the .Solar System, wo at once perceive it to be in motion. Again, if we compare the 
entire Solar System with tho more remote heavenly bodies, analogy wonld lead \ts to 
expect that our system may be in motion towards the Fixed Stars, and that these 
Stars themselves may only be fixed, relative to our own limited means of observation. 
To suppose the Fixed Stars to bo really motionless, would be as great a violation 
of analogical reasoning, as those theories inflict which deny the permanent characters 
of species. All the sciences adopt this mode of reasoning when the contemplated 
object is inaccessible to direct experiment or observation. On looking abroad into 
Nature, tho Chemist finds every thing in a state of composition. He nowhere dis- 
covers pure oxygen, chlorine, calcium, or potassium, because nearly all the unions 
which simple substances were capable of forming spontaneously have already occurred. 
Tho Naturalist is disposed to imagine that something similar to this may have taken 
place among the species of animals and plants ; but the Chemist analyzes the com- 
pounds of these substances himself, and he sees their combinations going on before 
his eyes. 'Tho Naturalist cannot bring forward one single instance of the de^e- 
ncration or transition of species from one form to another. 
The weak point of the Lamarckian doctrine, in the absence of positive proof, 
is a violation of one of the first rules of analogy. Mr Lyell correctly remarks, in 
his recent criticism on this subject, that “ no positive fact is cited to exemplify tho 
substitution of some entireig new sense, faculty, or organ, in the room of some other 
rendered useless. All the instances adduced go only to prove, that the dimensions 
and strength of members, and the perfection of certain attributes, may, in a long course 
of generations, be lessened and enfeebled by disuse ; or, on the contrary, be matured 
and augmented by active exertion, just as we know that the power of scent is feeble 
in the Greyhound, while its swiftness of pace and its acuteness of sight are remark- 
able ; — that the Harrier and Staghound, on the contrary, arc comparatively slow in 
their movements, but excel in the sense of smelling. It is evident, that if some well 
authenticated facts could have been adduced to establish one complete step in the 
progress of transformation, such as the appearance in individmals descended from a 
common stock, of a sense or organ entirely new, and a complete disappearance of some 
other enjoyed by their progenitors, that time alone, might then be supposed sufficient 
to bring about any amount of metamorphosis. The gratuitous assumption, therefore, 
cf a point so vital to the theory of transmutation, was unpardonable on the part of 
i(s advocate.” 
We have now seen that some Mammalia are capable of undergoing a very consi- 
derable variation, not only in their Instincts and Intelligence, but also in their ex- 
ternal forms ; — that tho variations which each individual can bo made to undergo by 
the circumstances in which it is placed arc but very rarely transmitted to posterity, 
while connate modifications usually end in becoming hereditary; and that there are 
certain limits beyond which no species has been observed to vary, so that wo are 
fully entitled to conclude, that a certain form was assigned to each species at the 
origin of things. 
GENER.VL REVIEW OF THE MAMMALIA COKTINUED. 
Forms to which the Domestic Animals have reverted on becoming wild Their 
modifications during the Idistorical era. 
If it be true that tho numerous varieties of the Cow, tho Horse, tho Dog, and other 
Domestic Mammalia, are the effects of tho slow and continued influence of certain 
causes, which, in the first instance, induce a departure from the primitive type in the 
evolution of connate varieties, and afterwards tran.smit the.so variations to posterity, 
giving rise to their several distinct races ;— it ought to follow, that in all these artifi- 
cial beings, whose characters Man has for a time rendered permanent, there should 
bo a continual tendency, when left to their own resources, to assume the form of the 
original type. On allowing the domestic animals to run wild,— on permitting them 
to snbstituto the wandering habits and precarious subsistence of mountains and 
forests for the uniform and regular diet of the stable, we ought to find that thc.r 
acquired characters disappear, that all the individuals bear that marked resemblance 
to each other, which will serve to indicate both the identity of their species, and 
the original form from which tho races have diverged. 
The experiments confirming the truth of this conclusion have long been per- 
formed on the largest scale in the immense continent of America. It is well known 
that the Europeans, on the first discovery of the New World, sought in vain for any 
vestige of that animal creation to which they had so long been familiarized. Those 
useful animals, without whose aid, in the first instance, tho civilization of Mim might 
have been indefinitely retarned, had to be transported to America to supply the im- 
mediate necessities of the earlier colonists. Soon, however, the accidental flight of 
some animals to the woods, hastened probably by tho abiuidant supply of food, and a 
favorable climate, which, in increasing their fecundity, rendered a vigilant care of 
them superfluous, a large proportion became absolutely wild, and the establishment 
of wild individuals in the immediate neighbourhood of tho tame herds soon exerted a 
direct modifying influence over the latter. Hence, in America, wo may see performed, 
on a magnificent scale, the converse of that gradual modification which the domestic 
