THE MAMMALIA— MAX AND BEASTS. 
73 
'^hicH it has contracted to the common fund of animal Nutrition, from whence the 
materials of its body have been derived. Thus the great drama of universal life is 
perpetually sustained; and though the individual actors undergo continual change, 
tlie same parts are ever filled by another and another generation ; renewing the face 
of the earth, and the bosom of the deep, with endless succession of life and 
happiness.” 
• GENERAL REVIEW OF THE MAMMALIA CONTINUED. 
The internal functions of the Mammalia in harmony with the revolutions of the 
Earthy and the laws of inanimate Natvre^General Relations to XAghtt Heaty 
and Electricity, 
It has already been shown, that the dimensions and forces of animals bear a certain 
determinate relation to the circumstances of their conditions*, — that the Creator has 
organized them so as to correspond accurately with their intended habitations. 
When an aquatic animal removes permanently to the air or earth, it receives an 
organization suited to that change. I’ho Frog is assigned the characters of a Fish 
while in its Tadpole state, and acquires those of a Reptile when it is designed also 
to reside upon the land. Rut this correspondence of animals to the circumstances of 
their condition is not confined merely to the media, whether air or water, in whicli 
they are intended to move; for their forces also bear a determinate relation to the 
earth, considered Mechanically as a mass of matter, or Astronomically in its relation 
to the other bodies of the Solar System. 
The dependance of all animal motions upon the attractive force of the Earth is suffi- 
ciently obvious. Each animal body is acted upon by Gravity, in proportion to its 
mass; in other words, it possesses weight; and in order that animals may exercise 
the power of moving, it is necessary that their forces shall bear a certain relation in 
excess to that of gravity, otherwise no motion could follow*. Their forces must also 
be proportioned to the resistance which gravity ofi’era to their exertions, or else ani- 
mals would lose their balance, their motions would proceed by jerks; at one time 
they would endanger their own safety by an excessive rapidity, at another by an 
excessive slowness; in all tbry would be devoid of grace, energy, and convenience. 
Animals would como into collision with other animals, or with harder substances than 
their own bodies; and this globe of Earth, like a machine out of order, would soon 
lie in a state of inactivity and disorganization. 
Mr "WhewcU remarks, that if the force of gravity were increased in any consi- 
<lerablc proportion at the surface of the earth, all the swiftness, and strength, and 
grace of animal motions must disappear. If, for instance, the earth were as largo as 
Jupiter, gravity would be eleven times what it is; the lightness of the Fawn, the 
speed of the Hare, the spring of the 'figer, could not exist with the existing muscu- 
lar powers of those animals; for Man to lift himself upright, or to crawl from place 
to place, would be a labour slower and more painful than the motion of the Sloth. 
The density and pressure of the air, too, would be increased to an intolerable extent, 
and the operation of respiration and others which depend upon these mechanical pro- 
perties, would be rendered laborious, mefFcctiial, and probably impossible. If, on the 
other hand, the force of gravity wore much lessened, inconveniences of an opposite 
kind would occur. The air would be too thin to breathe; the weight of our bodies, 
and of all the substances surrounding us, would become too slight to resist the per- 
petually-occurring causes of derangement and unsteadiness: we should feel a want of 
ballast in all our movements. Things would not bn where wo placed them, but 
Would slide asvay with the slightest push. We should have a difficulty in standing or 
walking, something like what we have on ship-board when the deck is inclined; and 
We should stagger helplessly through an atmosphere thinner tlian that which oppresses 
the respiration of the traveller on the tops of the highest mountains. 
The force of gravity depends upon the mass or quantity of matter in the Earth. 
For any reason that we can discover, this globe might have been as large as Saturn 
or Jupiter, its mean density might have been that of cork or of gold, in any of W'hicli 
eases the force of gravity would have been very different from what it is at present; 
and wc can easily imagine, that if every thing were seven times as heavy, or onc- 
seventh lighter than it actually is, animals could not exist in their present state. The 
Moon and Planets all differ in size and density from the Earth, anti from each other; 
and in general, the smaller seem to be nearest to the Sun, for our imperfect gaze fails 
to discover the lesser bodies which probably exist in the outward regions of the Solar 
System. For this reason, the inhabitants of other globes must be so different from 
®tirs, as to render it almost impossible for us to form any conception of their nature. 
Thus the Earth is not only the common source whence Animals and Plants 
derive their subsistence, but it is the common source of all animal motions, not only 
'u the reaction offered by its inertia, but in the looseness of that invisible tie which 
connects our bodies to its surface. Our relations to the earth are not even confined 
the surface, but extend to those remote depths which the minor and geologist con- 
^mplates only in imagination ; and every jiarticle of matter towards the centre exer- 
cises an influence in proportion to its magnitude. The intimate relation of the Earth 
to the inhabitants of its surface, has led all ages to regard it as the common mother 
cf all; and nations have b«^cn proud to con.sider (liomselves (antoch- 
*hones)y or sprung from ** the dust of the canh," — their native soil. 
is, however, in the great phenomena of Astronomy, in those revolutions of the 
heavenly bodies which have served to mark the epochs of time, that we perceive the 
^ore astonishing, because more unexpected, correspondence between these remote 
Vhenotuena, and tlie periodical functions of organized beings. 
^he diurnal revolutions of the globe arc always performed in the same time, being 
^hat which elapses between the appearance of a star on the meridian until it again 
*‘cturns to tho same meridian. This regular and con.''tant movement, constituting a 
*‘'h*rual day, forms the unit or measure of time, and gives rise to the periodical changes 
iJay and Night. All animals and plants, which decorate the surface of the enrih, 
P'trta.'.e in this revolution around its axis, and to this phenomenon all function" ot 
^fninalg, depending upon the pr(*sence or absence of Light, such as Sleeping anil 
>akmg, Hunger, stales of Exertion or Repose, hear an immediate n-fcrcnce. The 
^ ‘tenial clock-work of the anin'ml frame has been made to run for tivcuty-four iiours. 
when tho same states of the animal frame succeed each other in the same order, and 
in exact conformity with the revolutions of the globe. 
Besides this diurnal period of the animal clock-work regulated by tho diurnal 
revolution of twenty-four hours, there also exist periodical functions referring to 
divisions of weeks and months, as tho epochs of menstruation, also the incubations of 
Birds, which may endure for two or three weeks, and the gestations or internal in- 
cubations of tlie Mammalia, extending from three weeks to nine or eleven months. 
The year, or period of the Earth’s revolution round the Suu, is the most im- 
portant astronomical phenomenon in reference to organized beings. It is felt through 
every portion of animated Nature ; it measures the great epochs of their existence, 
and forms the limit of duration. t.o a multitude of animals of the Class of Insects in 
particular, and of Plants. All their functions are distributed in reference to the 
periods of the year. The annual species are horn in the Spring, the Summer be- 
comes the period of their puberty and reproduction, their fruits or productions 
appear in Autumn, and they die on the approach of Winter. Man, and the other 
persistent beings, from the Mammalia to 1‘rees and Herbs, experience more or less 
the influence of the seasons over their physiological functions. 
Spring, being the morning of tho year, is favorable to births and bodily growth ; 
it is in fact the period of youth, expansion, and gaiety. Experience proves that the 
human frame then undergoes, like Plants, its highest degree of growth and develop- 
ment. 
Summer, analogous to mid-day, is the season of heat, ardour, strength, and the 
highest development of the faculties. It corresponds with the age of puberty, and 
the impetuosity of the passions. The rutting period, with most animals, happens 
towards the summer solstice. 
Autumn is the evening of the year. Plants then yield their fruits, they aftenvards 
become ligneous and dry, and finally fade away. Animals, after performing the act 
of generation, cast their hair, skin, or feathers, and undergo that moulting which 
strips them of their more gaudy attire. This is the epoch when the faculties be- 
come concentrated, a period of melancholy and sadness. Vegetation ceases, and 
plants in general lose their foliage. 
Winter, the cold night of the year, renders the vegetable world dormant, and 
especially the cold-blooded animals. It is the season of repose, of nutrition, and 
internal repair, preparatory to future action. Animal bodies become inert, moist, 
and phlegmatic. Life is rendered at this period almost stationary and nullified; 
it remains either in a state of concentration, or in absolute torpidity. 
Thus, besides the nychthemeral periods, or diurnal revolutions, which regulate the 
daily functions of existence, the crises of maladies, the hours of repast or excretion, 
we have monthly periods of gestation and incubation, menstruation, rutting, and 
moulting, corresponding to the flux and teflux of the tides, to the periodical winds 
of the tropics, and the revolutions of the Moon. Again, tlie annual periods fix a 
limit to the lives of all annual and biennial species, and determine the periods of 
their gi'owth, the metamorphoses of Insects, with the phenomena of reproduction 
and decay among most animals. 
Thus the revolutions of our globe, and its relative situation to the heavenly bodies, 
maintain the circles of our existence in equilibrium with them. A philosophical 
Astrology may read our lives and destinies in the stars, which move in their curvi- 
linear orbits by tho same force that urges all Living Beings onwards in their physio- 
logical periods. Time, measured by the successive revolutions of our planet, draws 
onwards all the generations of Plants and Animals which decorate its surface ; it 
marks tho fatal hour to cacli individual, as it brings round the periods of love and tho 
necessities of nutrition. The f®tus of animals and the fruits of vegetables arrive to 
matui’ity at the appointed period. Each species of Mammalia has its fixed time of 
gestation, sufficient for the pro]>er elaboration of the foetus, which period may, how- 
ever, sometimes vary by a few <Uys in proportion to differences of food, temperature, 
or the season of the year. Minerals, on the other hand, are only moved by general 
impulses, without each of them partaking in a special activity. With them no period 
of time marks out their duration, whilst, with us, each pulsation of the heart, and 
every second of time, urges us onwards in the vital career, without the possibility of 
avoiding or retreating. 
The well-being of most animals is intimately connected with the degree in which 
they conform all their habits and functions to the periods of day and night. This is 
roost remarkable in Man, who in all ages has his fixed periods of tho day and night 
for food and repose, and this regular circle of actions has a direct reference to his 
intenml constitution, and independent of mere external stimuli. “ In the vova^es 
rccc]itly made into high northern latitudes, where the Sun did not rise for three 
mouths, the crews of the ships wore made to adhere, with the utmost punctuality, to 
the liabit of retiring to rest at nine, and rising a quarter before six, and they enjoyed, 
under circumstances the most trying, a state of salubrity quite remarkable. This 
shows that, according to the common constitution of such Men, the cycle- of twenty- 
four hours is very commodious, though not imposed on them by external circum- 
staiiccs.” Some Men arc naturally nyctuiopesy or night-eyed, such are Albinos and 
white Negroes, Dondos or Blafards, which cannot endure tho full blaze of dav- 
light. 
Among the Qua lnimana, several Howling A}>es (Mycctes senecrtlus axid Reehelnil) 
are cither nocturnal or at leaat crepuscular, preferring tho twilight of the morning and 
evening for their time of feeding and exertion. It is the same with certain Makis, 
who have thence derived their name of Eemur, from their haunting the twilight liko 
the shades (leraurus) of the departed. 
Tho Cheiroptera or Bats, especially tho Genus Noctilio, with the Galeopithoci or 
Flying-Cats; the Insectivora, such as tlie Hedgehogs, Shrews, and Molcu; the 
Plantigrada, such as the Bears and Badgers ; also the entire genus of Cals ; the 
Weasels, Polecats, and many Opossums, .are strictly nocturnal ; and this quality seems 
eminently appropriate to all those Carnivora or Marsupialia, which watch for their 
prey, and endeavour to surprise them while sleeping. Like assassins and brigands of 
our own species, llicy bury themselves in silence and obscurity to render their blows 
the more deadly. 
We fin I many crepuscular or semi-nocturnal species among tho RoduntU; which 
