298 
staedt regarded the jackal of Caucasus as the 
original source whence our domestic dogs are de- 
scended. Others again thought that the differ- 
ent kinds of dog have diverged fron the shep- 
herd’s dog, while some considered them all but as 
degenerations from the hyena, the wolf, or the 
fox. Thus it i8 precisely in those places where a 
fixed rule is most required that the breeding 
principle wholly fails, and we may seek in vain 
for any other. Blumenbach could propose none, 
but referred the determination of species to 
analogy and probability. ‘“ Fere desperem,” he 
observes, “posse aliunde quam ex ANatoaia et 
verisimilitudine notionem speciei in Zoologie 
studio depromi.” (I may almost despair of being 
able to derive the idea of species in the study of 
Zoology from any other source than analogy and 
probability.) Two races of animals which pos- 
sess a general resemblance, and differ only in 
those respects which have been observed to vary, 
and can be traced to some well-known causes of 
variation, must at once be admitted to belong to 
the same species ; but however near their gene- 
ral appearance may be, if they exhibit any dif- 
ference which, in all our experience of the ani- 
mal kingdom, has never been known to exist as 
a variety, they must be set down as distinct spe- 
cies. The proper determination of species rests, 
therefore, upon the knowledge of an immense 
number of facts, and forms one of the most diffi- 
cult, as it is one of the most important, subjects 
to which the naturalist can direct his attention. 
Thus Blumenbach considers the ferret to be 
merely a variety of the polecat, Mustela puto- 
rius, not because they generate together, for 
perhaps the experiment may not yet have been 
made, but because the former is white with red 
eyes ; and, from that well-known rule of analogy, 
that the same effects must be referred to the 
same causes, its origin is the same with those al- 
bino varieties produced daily among the domes- 
ticated mammalia. Again, the Indian elephant, 
Elephas Indicus, differs remarkably from that 
of Africa, HL. Africanus, in the number and form 
of its molar teeth. Whether these animals will 
engender together it is perhaps difficult to deter- 
mine ; but on examining every specimen which 
reaches this country, the same difference is 
found to exist. Further, we know of no analo- 
gous instance of variety in the formation of the 
molar teeth among wild or domesticated animals. 
We, therefore, do not hesitate to set down these 
two elephants as distinct species. 
There are other difficulties arising from the 
want of accurate information ; and these, in the 
present state of the science, occur but too fre- 
quently. For example, the skin of an animal 
arrives from the Cape of Good Hope. At the 
first glance it appears, perhaps, to be a specimen 
of the common Cape otter, Luwtra capensis, and 
this opinion may be further confirmed on ex- 
amining the structure of itsteeth. The colour of 
the breast and throat may seem of a purer white, 
SPECIES. 
and to be more extensive than usual, but this is a 
characteristic which might belong to a mere va- 
riety. On looking at the feet, we are much sur- 
prised at finding all the toes without nails, ex- 
cepting on the second and third of the hinder- | 
feet, where only a rude vestige of a nail can be 
observed. A carnassier without claws would 
seem an anomaly in creation. To suppose a 
being, compelled by its structure to live on ani- 
mal food, and yet to be refused by Nature the 
weapons fitted for seizing its prey, disturbs our 
ideas of final causes, and we delight to trace 
order and regularity in the works of. creation. 
The specimen must then be imperfect. It be- 
longs to an old individual ;—perhaps the claws 
may have dropped off through age or disease. 
We set it down, therefore, as a mere variety of 
the Lutra capensis. Some years afterwards, young 
individuals are brought with the nails entire ; 
the first view then seems abundantly confirmed ; 
perhaps even we applaud our own sagacity, and 
our extensive knowledge of final causes,—of those 
ends and uses for which the Creator designed the 
various parts of the animal world. Finally, an- 
other young individual is imported with all the 
characters of the original specimen, thus proving 
it not only to have been a distinct species, but 
entitling it to the rank of a separate genus—the 
Aonyx, or Nail-less otter of M. Lesson ; and one 
more instance is afforded of the inexhaustible 
variety in the works of nature. When we find 
that even the possession of claws is not always 
indispensable to the subsistence of the carnassier, 
we may thence derive the salutary caution, not 
to confide too implicitly in analogical reasoning, if 
we wish to form correct views regarding new or 
unknown natural objects. 
Since the supporters of the permanent charac- 
ters of species thus find it difficult to fix any 
very definite rule for determining them, and as 
the characters themselves are seen to run into 
innumerable varieties, two very different theories 
have been proposed. Linneus and Buffon as- 
serted that only a small number of stocks were 
originally created, from which all the existing 
species have degenerated and diverged, from the 
influence of climate, food, and domestication, aid- 
ed by a promiscuous intercourse, which has been 
limited only by their progeny ceasing to produce 
fertile races. On the other hand, Lamarck con- 
sidered that the form of the body, and all the 
characters of species, were the consequence of 
the habits, the manner of living, and other cir- 
cumstances, which have, in the course of time, 
given rise to the form of each species. Further, 
that man, and each higher animal, has originally 
risen from some lower division of the animal 
kingdom, by the gradual transition of the cha- 
racters of one species into another, but always 
from the lower to the higher, with the trans- 
mission of such commuted characters to their. 
posterity. These theories both agree in denying 
the fixed character of species. That of Linneus 
