ORGANIZED BEINGS— ANIMALS AND PLANTS. 



Every organized being produces otliers resembling it. Without this 

 provision, all species would become extinct, since death is the necessary 

 consequence of the continued action of life. Certain animals possess the 

 power of reproducing some of their parts, after these have been removed. 

 This power is termed eeproduction, and it is found in various degrees 

 of perfection, according to the species. 



In general, this power of renovating mutilated parts is found to exist most per- 

 fectly in the lower species of organized beings. The head of the snail (^Limax, Linn.) 

 may be cut off, and the whole organ, including its elegant telescopic eyes, will be re- 

 produced. The claws, feet, and feelers (or antenniE) of crabs and lobsters, as well as 

 the limbs of spiders, when amputated, are completely restored by the fresh growth 

 of new organs. When accident deprives a shark of its teeth, they are replaced with 

 facility. If the fins of fishes be cut, they will reunite, and the rays themselves will be 

 reproduced, provided only the small parts at their bases are left. The eyes of lizards, 

 though possessed of an intricate apparatus of coats and humours, if removed, will be 

 replaced by new eyes equal to the former. Even man and the higher animals possess 

 the same power, only restricted within narrower limits. Injuries to various parts of 

 our frame are speedily repaired, and the wounds heal. The effect of injury to a living 

 bone is curious. A new bone is produced round the old one ; which finally dies, and 

 is absorbed or discharged. The new bone, which at first was spongy in its texture, 

 and irregularly formed, assumes, in a few years, its natural dimensions, and all ap- 

 pearance of change is completely removed. Thus we see the bountiful provision of 

 Nature, and the effect of that principle of reproduction^ which restores most of the 

 organs of the body to their natural form and action, when deranged by injury or by 

 disease. 



Organized beings are developed with greater or less rapidity and perfec- 

 tion, according as they are placed in favorable or unfavorable circum- 

 stances. Heat, the quantity or quality of their nutriment, and other 

 causes, exercise considerable influence over them ; and this influence may 

 extend over the whole frame, or be confined only to certain organs. 

 Hence, it follows, that the resemblance between the progeny and its 

 parents can never be perfectly exact. These minor differences among 

 organized beings are called varieties. 



The different kinds of dog {Canis familiarise Linn.), of horse {Eqmcs cahallus, 

 Linn.), of sheep (Ovis aries, Desm.), are all varieties of the same species, and are pro- 

 duced by merely accidental causes, such as domestication, climate, &c. By cultivation, 

 the sloe has been transformed into the plum, and the crab-tree into the apple-tree. The 

 cauliflower and red cabbage, though apparently very different plants, are descended 

 from the same parents, — the wild Brassica oleracea, — a weed growing near the sea. 

 Mr Herbert relates, in the Horticultural Transactions, that he succeeded in raising, 

 from the natural seed of a highly-manured red cowslip, a primrose, a cowslip, oxlips 

 of the usual and other colours, a black polyanthus, a hose-in-hose cowslip, and a 

 natural primrose, bearing its flower on a polyanthus stalk ; — all these arc instances of 

 varieties, depending upon soil and situation. 



There is, however, no real ground for supposing that all the differences 

 observable in organized beings are the result of accidental circumstances. 

 Every thing hitherto advanced in favour of this opinion is purely conjec- 

 tural. On the contrarv, experience clearlyshows, that, in the actual state of 

 the globe, species vary only within very narrow limits ; and, as far as past 

 researches have extended, these limits are found to have been in ancient 

 times the same as at present. 



The French naturalists, who visited Egypt with Bonaparte, found the bodies of the 

 crocodile, the ibis, the dog, the cat, the bull, and the ape, which had been embalmed 

 three thousand years ago by the Egyptians as objects of veneration, to be perfectly 

 identical with the living species now seen in that country, even to the minutest bones 

 and the smallest portions of their skins. The common wheat, the fruits, seeds, and 

 other parts of twenty different species of plants, were also discovered, some of them from 

 closed vessels in the sepulchres of the kings ; and they resembled in every respect the 

 plants now growing in the East. The human mummies, also, exactly corresponded 

 with the men of the present day. 



We are, therefore, compelled to admit that certain forms have been 

 regularly transmitted to us from the first origin of tilings, without having 

 transgressed the limits assigned to them, [except in a slight degree, when 

 modified by certain accidental circumstances.] All beings, derived from 

 the same original form, are said to constitute a species; and the varieties 

 are, as has been stated, the accidental subdivisions of species. 



Generation appears to be the only means of ascertaining the Umits by 

 wliich varieties are circumscribed ; and we may therefore define a species 

 to be — a group or assemblage of individuals, descended, one from another, 

 or from common parents, or from others resembUng them, as much as 

 they resemble each other. However rigorous this definition may appear, 

 its application in practice to particular individuals is involved in many 

 diificulties, especially when we are unable to make the necessary experi- 

 ments. 



In conclusion, we shall repeat, that all living bodies are endowed with 

 the functions of absorption [by which they draw in foreign substances] ; 

 of assimilation [by which they convert them into organized matter] ; of 

 exhalation [by wliich they surrender their superfluous materials] ; of de- 



velopment [by which their parts increase in size and density] ; and of 

 generation [by which they continue the form of their species.] Birth and 

 death are universal limits to their existence: the essential character of 

 their structure consists in a cellular tissue or network, capable of con- 

 tracting; containing in its meshes fluids or gases, ever in motion : and the 

 bases of their chemical composition are substances, easily convertible into 

 hquids or gases ; or, into proximate principles, having great aflinity for each 

 other. Fixed forms, transmitted by generation, distinguish their species, 

 determine the arrangement of the secondary functions assigned to each, 

 and point out the part they are destined to perform on the great stage of 

 the universe. These organized forms can neither produce themselves, nor 

 change their characters. Life is never found separated from organization ; 

 and, whenever the vital spark bursts into a flame, its progress is attended 

 by a beautifully-organized body. The impenetrable mystery of the pre- 

 existence of germs alike defies observations the most delicate, and medi- 

 tations the most profound. 



We trace an individual to its parents, and these again to their parents. After a few 

 generations the clue is lost, and in vain we inquire, Wlience arose the first animal 

 of the species? and what produced the first germs from which have descended the 

 innumerable tribes of animals and plants, that we see in constant succession rising 

 around us? WTience did the species jian arise? Philosophical inquiry fails to lead 

 us through the labjTinth ; and we feel the force of the same principle which inspired 

 Adam, when he says, with* jMilton, 



" Thou sun, fair light. 

 And thou enlightened earth, so fresh and gay. 

 Ye hills and dales, ye rivers, woods, and plains. 

 And ye that Uve and move, fair creatures, teU, 

 Tell if you saw, how came I thus, how here, 

 Not of myself?" 



SECT. lU DIVISION or OEGANIZED BEINGS INTO ANIMALS AND PIANTS. 



Animals and Plants — Irritahility — Animals possess Intestinal Canals Circulating 



System — their Cliemical Composition — Respiration. 



Living or organized beings have been subdivided by universal consent, 

 from the earliest ages, into animals endowed with sensation and motion, 

 and into plants destitute of both, and reduced to the simple powers of 

 vegetation. 



Some plants retract their leaves when touched ; and all direct their roots 

 towards moisture, and their flowers or leaves towards air and light. Cer- 

 tain parts of plants even exhibit vibrations, unassignable to any external 

 cause. Yet, these different movements, when attentively examined, are 

 found to possess too little resemblance to the motions of animals, to au- 

 thorize us in considering them as proofs of perception and of volition. 



They seem to proceed from a power, possessed in general by all living substances, 

 of contracting and expanding when stimulated, — a power to which the name of 

 irritahilitij has been assigned. The fibres composing the heart of animals alter- 

 nately expand and contract, altogether independent of the will of the animal; and 

 thick hair will grow on the skins of some animals, when removed into a cold chmate. 

 As we neither ascribe volition nor sensation to the heart or to the hair, so we cannot 

 attribute these qualities to the heliotrope, to the sun-flower, or to the sensitive plant. 

 The nice distinction of character must be cautiously observed, between sensation and 

 mere irritability : like the higher powers of reason and instinct, they are 



" For ever separate, yet for ever near." 



The power of voluntary motion in animals necessarily requires cor- 

 responding adaptations, even in those organs simply vegetative. Animals 

 cannot, like plants, derive nourishment from the earth by roots ; and hence 

 they must contain within themselves a supply of ahment, and carry the 

 reservoir with them. From this circumstance is derived the first trait in 

 the character of animals. They must possess an intestinal canal, from 

 which the nutritive fluid may penetrate, by a species of internal roots, 

 through pores and vessels into all parts of the body. The organization 

 of this cavity, and of the parts connected with it, ought to vary accord- 

 ing to the nature of the aliments, and the transformations necessary to 

 supply the juices proper to be absorbed; whilst the atmosphere and the 

 earth have only to present to vegetables the juices already prepared, 

 when they are uumediately absorbed. 



Animal bodies, having thus to perform more numerous and varied func- 

 tions than plants, ought.to possess a much more complicated organization ; 

 and, in consequence of their several parts having the power of changing 

 their position relatively to each other, it becomes necessary that the motion 

 of the fluids should be produced by internal causes, and not be altogether 

 dependent on the external influences of heat and of the atmosphere. 

 This is the reason that aoimals are endowed with a circulating st/stem, or 



