THE MAMMALIA—MAN AND BEASTS. 



73 



which 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 hfe is 

 pernetuaUy sustained; and though the indivitVual actors undergo continual change, 

 the same parts are ever filled by another and another generation; renci-ving the face 

 of the earth, and the bosom of the deep, with endless succession of life and 

 happiness." 



GEKERAL REVIEW OF THE MAMMALIA CONTINUED. 



TJie inte-mal functions of the Mammalia in harmovy with the revolutions of the 



Earthi and the laws of inanimate Nature — General Relations to Lights Heat, 



and Electricitjj. 

 Jt 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. The 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. But this correspondence of animals to the circumstances of 

 their condition is not confined merely to the media, whether air or water, in which 

 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 offers 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 they would be devoid of grace, energy, and convenience. 

 Animals would come into collision with other animals, or with harder substances than 

 their own bodies; and this globe of Earth, liLe 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- 

 derable 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 large as 

 Jupiter, gravity would be eleven limes what it is; the lightness of the Fawn, the 

 ■peed of the Hare, the spring of the Tiger, 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 tin: 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, ineffectual, and probably impossible. If, on the 

 other hand, the force of gravity were 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 be where we placed them, but 

 would slide away with the slightest push. We should have a difficulty in standmg or 

 walking, something like what we have on ship-board when the deck is inclined ; and 

 we should stagger lielplessly through an atmosphere thinner than 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 which 

 cases the force of gravity would have been very different from what it is at present; 

 and we can easily imagine, that if every thing were seven times as heavy, or one- 

 levcnth h"hter than it actually is, animals could not exist in their present state. The 

 Moon and Planets all difler in size and density from the Earth, and from each other ; 

 and in ^enera!, 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 fi'om 

 ours, 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 

 in the reaction offered by its inertia, but in the looseness of that invisible tie which 

 comiects our bodies to its surface. Our relations to the earth are not even confined 

 to the surface, but extend to those remote depths which the miner and geologist con- 

 templates only in imagination; and every particle of matter towards the centre exer- 

 cises an influence in proportion to its magnitude. The intimate relation of the Earth 

 to tbe inhabitants of its surface, has led all ages to regard it as the com.mon mother 

 of all; and nations have bi^en proud to consider themselves etvroyc&oyi; (^autoch- 

 thones)., or sprung from ** the dust of the earth," — their native soil. 



It 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 

 more astonishing, because more unexpected, correspondence between these remote 

 phenomena, and the periodical functions of organized beings. 



The diurnal revolutions of thi? globe are always performed in the same time, being 

 thit which elapses between the appearance of a star on the meridian until it again 

 returns to the same meridian. This regular and constant movement, constituting a 

 sidereal day, fori*;s the unit or measure of time, and gives rise to the periodical changes 

 of Day and Night. All animals and plants, which decorate the surface of the cai'th, 

 partake in this revolution around its axis, and to this phenomenon all functions of 

 auioidls, depending upon the presence or absence of Light, such as Sleeping and 

 ^Vaki^g, Hunger, states of Exertion or Repose, bear an immediate reference. The 

 i I'.erual clock-work of the animal frame has been made to run for twenty-four hours, 

 19 



when the 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 the diurnal 

 revolution of twenty -four hours, there also exist periodical functions referring to 

 divisions of weeks and months, as the epochs of menstruation, also the incubations of 

 Birds, which may endure for two or three weeks, and the gestations or internal in- 

 cubations of the Mammalia, extending from three weeks to nine or eleven months. 



The year, or period of the Earth's revolution round the Sun, is the most im- 

 portant astronomical phenomenon in reference to organized beings. It is felt through 

 every portion of animated Nature ; it measures the greet epochs of their existence, 

 and forms the limit of duration to 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 born in the Spring, the Summer be- 

 comes the period of their puberty and reproduction, their fruits or productions 

 appear in Autumn, and thoy die on the approach of Winter. Man, and the other 

 persistent beings, from the Mammaha to Trees and Herbs, experience more or less 

 the influence of the seasons over their physiological functions. 



Spring, being the morning of the year, is favorable to births and bodily grov.th ; 

 it is in fact the period of youth, expansionv 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 afterwards 

 become ligneous and dry, and finally fade away. Animals, aft^-'r 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 tlie epoch when the faculties be- 

 come concentrated, a period of melancholy and sadness. Vegetation ceases, and 

 plants in general lose their folinge. 



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 nuUified; 

 it remains either in a state of concentration, or in absolute torpidity. 



Thus, besides the nychtheraeral 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 reflux of the tides, to the periodical winds 

 of the tropics, and the revolutions of the Moon. Again, the annual periods fix a 

 limit to the lives of all annual and biennial species, and determine the periods of 

 their growth, 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 hves and destinies in the stars, which move in their curvi- 

 linear orbits by the 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 the fatal hour to each individual, as it brings round the periods of love and the 

 necessities of nutrition. The foetus of animals and the fruits of vegetables arrive to 

 maturity at the appointed period. Each species of Mammalia has its fixed time of 

 gestation, sulhcient for the proper elaboration of the fcctus, which period may, how- 

 ever, sometim.es vary by a few days 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 s^iccial 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 

 most remarkable in flian, who in all ages has his fixed periods of the day and night 

 for food and repose, and this regular circle of actions has a direct reference to his 

 internal constitution, and independent of mere external stimuli. " In the rova^-es 

 recently made into high northern latitudes, where the Sun did not rise for three 

 months, the crews of the ships were made to adhere, with the utmost punctuality, to 

 the habit of retiring to rest at nine, and rising a quarter before six, and they enjoyed. 

 Tinder 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- 

 stances." Some Jlen are naturally nyctalopes, or night-eyed, such arc Albinos and 

 white Negroes, Dondos or Blafards, which cannot endure the full blaze of dav- 



light. 



Among the Quadrumana, several Howhng Apes {Mycctes senemdns and Dedzehid) 

 are either nocturnal or at least crepuscular, preferring the 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 Lemur, from their haunting the twilight like 

 the shades (lemures) of the departed. 



The Cheiroptera or Eats, especially the Genus Noctilio, with the Galeopitheci or 

 Flying-Cats; the Insectivora, such as the Hedgehog?, Shrews, and Moles; the 

 Plantigrada, such as the Bears and Badgers ; also the entire genus of Cats ; Iho 

 Weasels, Polecats, and many Opossums, are strictly nocturnal ; and this quality seems 

 eminently appropriate to all those Carnivora or Marsupialia, which watch for their 

 prev, and endeavour to surprise them while sleeping. Like assassins and brigands of 

 our own species, they bury thcmseives in silence and obscuriy to render their blows 

 the more deadly. 



We fn 1 many crepuscular or semi -nocturnal ppecies amonj^ the P.oJentia, wht'jli 



