NATURAL HISTORY 



analysed in the several departments of General Physics. We ought, in treat- 

 ing of Natural History, to employ precisely the same methods as in the Ge- 

 neral Sciences ; and, therefore, we endeavour to adopt them, whenever the 

 subjects under examination become sufficiently simple to permit that mode 

 of investigation. But as this is seldom practicable, there arises, hence, an 

 essential difference between the General Sciences and Natural History. 

 For, in the former, the phenomena are examined under circumstances 

 completely within the reach of the inquirer, who arrives, by analysis, at 

 general laws; while, in the latter, they are removed, by unalterable con- 

 ditions, beyond his control. In vain, he attempts to disengage them from 

 the influence of general laws, already ascertained. He cannot reduce the 

 problem to its elements, and, like the experimental philosopher, withdraw 

 successively each condition ; but he must reason upon all its conditions 

 at once, and only arrive, by conjecture, at the probable result of such an 

 analysis. Let him seek to ascertain, by direct experiment, any one of 

 the numerous phenomena essential to the hfe of an animal, though but 

 slightly elevated in the scale of being, 



" And ere he touch" the vital spark— 'tis fled." 



Thus, it appears that, while Mechanics has become a science chiefly of 

 CALCULATION, and Chemistry of experiment. Natural History will long re- 

 main, in most of its departments, a science wholly of observation. 



The latter part of this remark must, however, he restricted to the early stages of 

 Natural History; because, in its more matured condition, it becomes a science of 

 demonstration. Every branch of physics has one leading object in view, and that is, 

 the discovery of the ultimate laws of Nature. Philosophy regards this as of primai-y 

 importance ; while utility is held only as of secondary rank. Science, in its most 

 comprehensive sense, is a superstructure founded on facts, or acquired by experience ; 

 and hence, in its early stages, we consider it as entirely limited to observation: but 

 when we have learned to generalize, and find that truths agree in their several relations, 

 we have arrived at the demonstrative part of the science. It is not, therefore, from 

 a mere knowledge of correct nomenclature, or from a capacity to recognize at sight a 

 natural object, that we are entitled to apply the name of scientijie knowledge to Na- 

 tural History ; but only when we have succeeded, by observation, in deducing the laws 

 which regulate these objects, in their relations to smTouncUng beings. 



These three terms. Calculation, Observation, and Experiment, express, 

 with suflScient accuracy, the manner of cultivating the several branches 

 of Physical Science ; but, by exhibiting among them very different degrees 

 of certainty, they indicate, at the same time, the ultimate point to which 

 Chemistry and Natural History ought to tend, in order to rise nearer to 

 perfection. Calculation, in a manner, sways Nature; it determines the 

 phenomena more exactly than can be done by observation alone : Expe- 

 riment obliges Nature to unveil: Observation watches when she is refrac- 

 torj', and seeks to surprise her. 



Natural History employs with advantage, on many occasions, a principle 

 of reasoning peculiar to itself, termed the conditions of existence, or, more 

 commonly, Jinal causes. As nothing can exist except it contains within 

 itself all the conditions which render existence possible, it is evident, that 

 tliere ought to be such a mutual adaptation of the various parts of each 

 being among themselves, and such an accommodation of their structure 

 to the circumstances of surrounding beings, as to render possible the ex- 

 istence of the whole. The analysis of these conditions often leads to the 

 discovery of general laws, with a clearness of demonstration, surpassed 

 only by the evidence of direct experiment or calculation. 



It was by the knowledge of this principle, that the celebrated Dr William Harvey 

 was enabled to discover the circulation of the blood in ftlan. The Honourable Robert 

 Boyle relates his conversation with Dr Harvey on this subject, in the followino- words: 

 — " I remember, that when I asked our famous Harvey, in the only discourse I 

 had with him (which was but a little while before he died,) what were the thinfrs 

 which induced him to think of a circulation of the blood? he answered me, that when 

 he took notice that the valves in the veins of so many parts of the body were so 

 placed, that they gave free passage to the blood towards the heart, but opposed the 

 passage of the venal blood the contrary way, he was invited to think, that so provident 

 a cause as Nature had not placed so many valves without design: and no design seemed 

 more probable than that, since the blood could not well (because of the interposin<^ 

 valves,) be sent by the veins to the limbs, it should be sent through the arteries and 

 return through the veins, whose valves did not oppose its course that way." It is 

 evident from this, and many other similar instances, that, in examining the subjects of 

 Natural History, we shall best advance the science, by considering attentively the uses 

 and ends designed by Nature in their formation, and the functions which their organs 

 are destined to perform. This manner of investigation has been objected to by some 

 philosophers, among whom is Des Cartes, as being a presumptuous attempt on the 

 part of human reason, far above its powers, to penetrate mto the secret designs of the 

 Creator. The following passage, extracted from the works of JMr Boyle above quoted, 

 forms a satisfactory answer to this objection: — " Suppose that a countryman, being in 

 a clear day brought into the garden of some famous mathematician, should see there 

 one of the curious gnomonic instruments, that show at once the place of the sun in 

 the zodiac, his declination from the equator, the day of the month, the length of the 

 day, 8:c. kc, it would indeed be presumptuous in him, being unacquainted both with 



the mathematical disciplines, and the several intentions of the artist, to pretend or think 

 himself able to discover all the ends for which so cxu-ious and elaborate a piece waa 

 framed: but when he sees it furnished with a style, with horary lines and numbers, 

 and, in short, with all the requisites of a sun-dial, and manifestly perceives the sha- 

 dow to mark from time to time the hour of the day, it would be no more a presump- 

 tion than an error in him to conclude, that (whatever other uses the instrument was fit 

 or was designed for,) it is a sun-dial, and was meant to show the hour of the day." 

 The whole science of Natural History teems with instances, showing the successful 

 apphcation of the general principle called the conditions of existence. Thus, when we 

 see an animal, possessed of a capacious stomach, long intestines, and a massive struc- 

 ture, we may safely infer that it is herbivorous, or feeding on vegetables, slow in its 

 movements, and of timid and gentle habits. On the contrary, when we find an 

 animal with short intestines, straight stomach, and armed with weapons of offence, we 

 immediately conclude it to be carnivorous, or feeding upon flesh, and of a fierce and 

 active disposition. 



It is further observed by the author, in his Lectures on Comparative Anatomy, that 

 the construction of the ahmentary canal determines, in a manner perfectly absolute, the 

 kind of food on which the animal is nourished. For, if the animal did not possess, in 

 its senses and organs of motion, the means of distinguishing the kinds of aliment suited 

 to its nature, it is obvious that it coxdd not exist. An animal, therefore, which can 

 only digest flesh, must, to preserve its species, have the power of discovering its prey, 

 of pursuing, of seizing, of overcoming, and of tearing it in pieces. It is necessary, 

 then, that the animal should have a penetrating eye, a quick smell, a swift mo- 

 tion, address and strength in the jaws and talons. Agreeably to this necessity, a 

 sharp tooth, fitted for cutting flesh, is never co-existent in the same species with a 

 hoof covered with horn, which can only support the animal, but cannot grasp any 

 thing : hence the law, according to which all hoofed animals are herbivorous, and also 

 those still more detailed laws, which are but corollaries to the iirst, that hoofs indicate 

 molar teeth or grinders with flat crowns, a very long alimentary canal, with a ca- 

 pacious and multiplied stomach. 



It is only after having exhausted all the laws of general physics, and 

 the conditions of existence, that we are compelled to resort to the simple 

 laws of observation. The most eil'ectual mode of deducing these is by 

 comparison; by observing the same body successively in the various po- 

 sitions in which it is placed by Nature ; and by comparing different bodies 

 with each other, until we obtain a knowledge of some constant relations 

 between their structure and the phenomena exhibited by them. These 

 various bodies thus form a species of experiments, performed entirely by 

 Nature's hand, where different parts of each are supplied or abstracted, 

 as we would desire to treat them in our laboratories; and the results of 

 these additions or abstractions are presented to us spontaneously. We 

 are thus enabled to deduce the invariable laws influencing these relations, 

 and to apply them in a manner, similar to the laws determined by general 

 physics. Could we but incorporate these laws of observation with the 

 general laws of physics, either directly or by means of the principle called 

 the conditions of existence, the system of natural science would be com- 

 plete, and the mutual influence of all beings would be perceived through- 

 out the whole. To approach this great end the efforts of naturalists should 

 be steadily directed. 



All researches of this kind presuppose that we have the means of dis- 

 tinguishing with certainty, and of describing to others with accuracy, 

 the objects under investigation ; otherwise, we shall be continually hable 

 to fall into confusion, amidst the innumerable beings which surround us. 

 Natural History ought, therefore, to have for its basis, what has been tech- 

 nically termed a system of nature, or a methodical and extensive catalogue, 

 arranged with divisions and subdivisions, in which all beings shall bear 

 suitable names and distinct characters* That we may always be able to 

 discover the character of any particular being from knowing its name, or 

 the name from knowing its specific character, we must found this pecuhar 

 description upon some essential or permanent properties of the being. We 

 must not derive the character from habits, or colour alone, as these proper- 

 ties are ever liable to be modified by external circumstances, but from 

 internal organization or composition. 



When Natural History was in its infancy, the objects were few and easily remem- 

 bered. Systems of classification were either neglected as unnecessary, or confined 

 only to those general divisions and subdivisions, which it was impossible to overlook. 

 But ever since the days of Aristotle, A.C. 330, when Alexander the Groat had in- 

 creased the number of known species of animals by some of the productions of the 

 conquered East, the necessity of a precise system of classification has been univer- 

 sally admitted; and now, the progress of geographical knowledge has enlarged the 

 bounds of the science to so vast an extent, and disclosed a variety so inconceivable 

 of forms hitherto unknown, that the naturalist would, without classification, be over- 

 whelmed with endless details. Yet the different kinds of animals are daily becoming 

 more numerous by the contributions of enlightened travellers. In 1750, the number 

 of distinct species of insects was estimated at 20,000, and now it cannot be less 

 than 100,000. And when it is considered how small a part of the globe has been 



* The word character, in Natural History, denotes that peculiar description of an 

 object which distinguishes it from all others. Thus we say, the character of man 

 is, " Teeth of three kinds, posterior extremities furnished with feet, anterior with 

 hands, &<:. &c.". — Translator. 



