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 ft-om 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 maintain 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 Mouflon and Siberian Argali ; and the common 

 Goat from the Persian and Caucasian Goats with the Ibex. We know that these 

 iniraals 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 are defective; but from analogy we might infer that a very 

 small part of their varieties 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 the body and the parts of the animal. With new forms, new 

 faculties have been acquired; and thus gradually Nature has produced the animals as 

 we now see them. 



We 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 

 13 as indispensable in maintaining the successive transition of forms, as in originally 

 creating them. Lamarck himself was well aware of this, for he observes, " When I 

 see that Nature has 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 wantSy 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 the 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 hmbs 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 the characters of the Flying 

 Squirrels (Pteromys), 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, unitmg not only the fore and 

 hind legs, but even the tail with the hinder feet, as well as the fingers with each 

 other. These now form our Flying Lemurs (Galeopitheats). 



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 members, but an extraordinary elongation of the fingers of 

 the anterior limbs, with large intermediate membranes, so that at length they con- 

 stituted those singulai- wings which we find in the Bats ( VespertiJio) . 



'* So great is the power of habit," observes M. Lamarck, *' that it singularly 

 affects even 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." 



LTpon this theory, it was requisite that the higher orders of animals should be re- 

 garded as of the greatest antiquity, a longer time being necessary for their transition 

 from those simple fwms, 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 the latter is the true cradle of the whole Animal Kingdom. In 

 fact, we still see that the least perfect animals are not only the most numerous, but 

 that they either live solely in the water, or in those very moist places, where Nature 

 has performed, and continues to perform, undej favorable circumstances, her direct 

 or spontaneous generations ; and there, in the first place, she gives rise to the most 

 simple animalcules, from which have proceeded all the animal creation." — (Philoso- 

 phie Zoologique, tom. 2, p. 456). 



We must remark, that there has never yet 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 species known to have lost any of their senses or 

 powers to make way •'or new ones. It must further be observed that, while we have 

 never found any ©f these transitions in circumstances within the sphere ef our 

 investigations, Lamarck places them precisely in those, where they cannot be proved 

 or disproved by direct observation. Wliere did these transitions begin? In 

 the abysses of the Ocean, where Man has never penetrated, and where myriads of 

 beings lie concealed from his observation, perhaps for ever. 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 the 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 succissively perforaieAf which. hai"e diversified the known animal--^, 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 be a pendulum mounted and in 

 motion, each generation would consider this pendulum really to be at rest, never 

 having seen it change in the 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 objects 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 inaccessible 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, we at once perceive it to be in motion. Again, if we compare the 

 entire Solar System with the more remote heavenly bodies, analogy would lead us 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 be 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, the 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. 

 The 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. The Naturalist cannot bring forward one single instance of the dege- 

 neration 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 the 

 substitution of some entirely 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, are comparatively slow in 

 their movements, but excel in the sense of smelUng. It ig 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 individuals 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 

 its advocate." 



We have now seen that some Mammalia are capable of undergoing a very consi- 

 derable variation, not only in their Instincts and IntelUgence, but also in their ex- 

 ternal forms ;— that the variations which each individual can be made to undergo by 

 the circumstances in which it is placed are but very rarely transmitted to posterity, 

 while connate modifications usually end in becoming hereditary; — and that there are 

 certain hmits beyond which no species has been observed to vary, so that we are 

 fully entitled to conclude, that a certain form was assigned to each species at the 

 origin of things. 



GENERAL REVIEW OF THE MAMMALIA CONTINUED. 



Forms to which the Domestic Animals have reverted on becoming wild Their 



modifications during the Historical era. 



If it be true that the numerous vai-ieties of the Cow, the Horse, the Dog, and other 

 Domestic Mammalia, are the eflrects of the 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 transmit these 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 

 be a continual tendency, when left to their owm resources, to assume the form of the 

 original type. On allowing the domestic animals to run wild, — on permitting them 

 to substitute the wandering habits and precarious subsistence of mountains and 

 forests for the uniform and regular diet of the stable, we ought to find that their 

 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 the 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. *rhose 

 useful animals, without whose aid, in the first instance, the civihzation of Man might 

 have been indefinitely retaroed, had to be transported to America to supply the im- 

 mediate necessiiies of the earlier colonists. Soon, however, the accidental flight of 

 some animals to the woods, hastened probably by the abundant supply of food, and a 

 favorable chmate, 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 the tame herds, soon exerted a 

 direct modifying influence over the latter: Hence, in America, we may see performed, 

 on a magnificent scale, the converse of that gradual modification which the domestic 



