Part 12

4. It should nevertheless be observed, that there is one kind of stimulus, which though it be employed in quantity beyond its usual state, seems to increase the production of sensorial power beyond the expenditure of it (unless its excess is great indeed) and thence to give permanent strength and energy to the system; I mean that of volition. This appears not only from the temporary strength of angry or insane people, but because insanity even cures some diseases of debility, as I have seen in dropsy, and in some fevers; but it is also observable, that many who have exerted much voluntary effort during their whole lives, have continued active to great age. This however may be conceived to arise from these great exertions being performed principally by the organs of sense, that is by exciting and comparing ideas; as in those who have invented sciences, or have governed nations, and which did not therefore exhaust the sensorial power of those organs which are necessary to life, but perhaps rather prevented them from being sooner impaired, their sensorial power not having been so frequently exhausted by great activity, for very violent exercise of the body, long continued, forwards old age; as is seen in post-horses that are cruelly treated, and in many of the poor, who with difficulty support their families by incessant labour.

III. _Theory of the Approach of Age._

The critical reader is perhaps by this time become so far interested in this subject as to excuse a more prolix elucidation of it.

In early life the repetition of animal actions occasions them to be performed with greater facility, whether those repetitions are produced by volition, sensation, or irritation; because they soon become associated together, if as much sensorial power is produced between every reiteration of action, as is expended by it.

But if a stimulus be repeated at uniform intervals of time, the

## action, whether of our muscles or organs of sense, is performed with

still greater facility and energy; because the sensorial power of association mentioned above, is combined with the sensorial power of irritation, and forms part of the diurnal chain of animal motions; that is, in common language, the acquired habit assists the power of the stimulus; see Zoonomia, Vol. I. Sect. XXII. 2. and Sect. XII. 3. 3.

On this circumstance depends the easy motions of the fingers in performing music, and of the feet and arms in dancing and fencing, and of the hands in the use of tools in mechanic arts, as well as all the vital motions which animate and nourish organic bodies.

On the contrary, many animal motions by perpetual repetition are performed with less energy; as those who live near a waterfall, or a smith's forge, after a time, cease to hear them. And in those infectious diseases which are attended with fever, as the small-pox and measles, violent motions of the system are excited, which at length cease, and cannot again be produced by application of the same stimulating material; as when those are inoculated for the small-pox, who have before undergone that malady. Hence the repetition, which occasions animal actions for a time to be performed with greater energy, occasions them at length to become feeble, or to cease entirely.

To explain this difficult problem we must more minutely consider the catenations of animal motions, as described in Zoonomia, Vol. I. Sect. XVII. The vital motions, as suppose of the heart and arterial system, commence from the irritation occasioned by the stimulus of the blood, and then have this irritation assisted by the power of association; at the same time an agreeable sensation is produced by the due actions of the fibres, as in the secretions of the glands, which constitutes the pleasure of existence; this agreeable sensation is intermixed between every link of this diurnal chain of actions, and contributes to produce it by what is termed animal causation. But there is also a degree of the power of volition excited in consequence of this vital pleasure, which is also intermixed between the links of the chain of fibrous actions; and thus also contributes to its uniform easy and perpetual production.

The effects of surprise and novelty must now be considered by the patient reader, as they affect the catenations of action; and, I hope, the curiosity of the subject will excuse the prolixity of this account of it. When any violent stimulus breaks the passing current or catenation of our ideas, surprise is produced, which is accompanied with pain or pleasure, and consequent volition to examine the object of it, as explained in Zoonomia, Vol. I. Sect. XVIII. 17, and which never affects us in sleep. In our waking hours whenever an idea of imagination occurs, which is incongruous to our former experience, we feel another kind of surprise, and instantly dissever the train of imagination by the power of volition, and compare the incongruous idea with our previous knowledge of nature, and reject it by an act of reasoning, of which we are unconscious, termed in Zoonomia, "Intuitive Analogy," Vol. I Sect. XVII. 7.

The novelty of any idea may be considered as affecting us with another kind of surprise, or incongruity, as it differs from the usual train of our ideas, and forms a new link in this perpetual chain; which, as it thus differs from the ordinary course of nature, we instantly examine by the voluntary efforts of intuitive analogy; or by reasoning, which we attend to; and compare it with the usual appearances of nature.

These ideas which affect us with surprise, or incongruity, or novelty, are attended with painful or pleasurable sensation; which we mentioned before as intermixing with all catenations of animal actions, and contributing to strengthen their perpetual and energetic production; and also exciting in some degree the power of volition, which also intermixes with the links of the chain of animal actions, and contributes to produce it.

Now by frequent repetition the surprise, incongruity, or novelty ceases; and, in consequence, the pleasure or pain which accompanied it, and also the degree of volition which was excited by that sensation of pain or pleasure; and thus the sensorial power of sensation and of volition are subducted from the catenation of vital

## actions, and they are in consequence produced much weaker, and at

length cease entirely. Whence we learn why contagious matters induce their effects on the circulation but once; and why, in process of time, the vital movements are performed with less energy, and at length cease; whence the debilities of age, and consequent death.

ADDITIONAL NOTES. VIII.

REPRODUCTION.

But Reproduction with ethereal fires New life rekindles, ere the first expires.

## CANTO II. l. 13.

I. The reproduction or generation of living organized bodies, is the great criterion or characteristic which distinguishes animation from mechanism. Fluids may circulate in hydraulic machines, or simply move in them, as mercury in the barometer or thermometer, but the power of producing an embryon which shall gradually acquire similitude to its parent, distinguishes artificial from natural organization.

The reproduction of plants and animals appears to be of two kinds, solitary and sexual; the former occurs in the formation of the buds of trees, and the bulbs of tulips; which for several successions generate other buds, and other bulbs, nearly similar to the parent, but constantly approaching to greater perfection, so as finally to produce sexual organs, or flowers, and consequent seeds.

The same occurs in some inferior kinds of animals; as the aphises in the spring and summer are viviparous for eight or nine generations, which successively produce living descendants without sexual intercourse, and are themselves, I suppose, without sex; at length in the autumn they propagate males and females, which copulate and lay eggs, which lie dormant during the winter, and are hatched by the vernal sun; while the truffle, and perhaps mushrooms amongst vegetables, and the polypus and taenia amongst insects, perpetually propagate themselves by solitary reproduction, and have not yet acquired male and female organs.

Philosophers have thought these viviparous aphides, and the taenia, and volvox, to be females; and have supposed them to have been impregnated long before their nativity within each other; so the taenia and volvox still continue to produce their offspring without sexual intercourse. One extremity of the taenia, is said by Linneus to grow old, whilst at the other end new ones are generated proceeding to infinity like the roots of grass. The volvox globator is transparent, and carries within itself children and grandchildren to the fifth generation like the aphides; so that the taenia produces children and grandchildren longitudinally in a chain-like series, and the volvox propagates an offspring included within itself to the fifth generation; Syst. Nat.

Many microscopic animals, and some larger ones, as the hydra or polypus, are propagated by splitting or dividing; and some still larger animals, as oysters, and perhaps eels, have not yet acquired sexual organs, but produce a paternal progeny, which requires no mother to supply it with a nidus, or with nutriment and oxygenation; and, therefore, very accurately resemble the production of the buds of trees, and the wires of some herbaceous plants, as of knot-grass and of strawberries, and the bulbs of other plants, as of onions and potatoes; which is further treated of in Phytologia, Sect. VII.

The manner in which I suspect the solitary reproduction of the buds of trees to be effected, may also be applied to the solitary generation of the insects mentioned above, and probably of many others, perhaps of all the microscopic ones. It should be previously observed, that many insects are hermaphrodite, possessing both male and female organs of reproduction, as shell-snails and dew-worms; but that these are seen reciprocally to copulate with each other, and are believed not to be able to impregnate themselves; which belongs, therefore, to sexual generation, and not to the solitary reproduction of which I am now speaking.

As in the chemical production of any new combination of matter, two kinds of particles appear to be necessary; one of which must possess the power of attraction, and the other the aptitude to be attracted, as a magnet and a piece of iron; so in vegetable or animal combinations, whether for the purpose of nutrition or for reproduction, there must exist also two kinds of organic matter; one possessing the appetency to unite, and the other the propensity to be united; (see Zoonomia, octavo edition, Sect. XXXIX. 8.) Hence in the generation of the buds of trees, there are probably two kinds of glands, which acquire from the vegetable blood, and deposite beneath the cuticle of the tree two kinds of formative organic matter, which unite and form parts of the new vegetable embryon; which again uniting with other such organizations form the caudex, or the plumula, or the radicle, of a new vegetable bud.

A similar mode of reproduction by the secretion of two kinds of organic particles from the blood, and by depositing them either internally as in the vernal and summer aphis or volvox, or externally as in the polypus and taenia, probably obtains in those animals; which are thence propagated by the father only, not requiring a cradle, or nutriment, or oxygenation from a mother; and that the five generations, said to be seen in the transparent volvox globator within each other, are perhaps the successive progeny to be delivered at different periods of time from the father, and erroneously supposed to be mothers impregnated before their nativity.

II. Sexual as well as solitary reproduction appears to be effected by two kinds of glands; one of which collects or secretes from the blood formative organic particles with appetencies to unite, and the other formative organic particles with propensities to be united. These probably undergo some change by a kind of digestion in their respective glands; but could not otherwise unite previously in the mass of blood from its perpetual motion.

The first mode of sexual reproduction seems to have been by the formation of males into hermaphrodites; that is, when the numerous formative glands, which existed in the caudex of the bud of a tree, or on the surface of a polypus, became so united as to form but two glands; which might then be called male and female organs. But they still collect and secrete their adapted particles from the same mass of blood as in snails and dew-worms, but do not seem to be so placed as to produce an embryon by the mixture of their secreted fluids, but to require the mutual assistance of two hermaphrodites for that purpose.

From this view-of the subject, it would appear that vegetables and animals were at first propagated by solitary generation, and afterwards by hermaphrodite sexual generation; because most vegetables possess at this day both male and female organs in the same flower, which Linneus has thence well called hermaphrodite flowers; and that this hermaphrodite mode of reproduction still exists in many insects, as in snails and worms; and, finally, because all the male quadrupeds, as well as men, possess at this day some remains of the female apparatus, as the breasts with nipples, which still at their nativity are said to be replete with a kind of milk, and the nipples swell on titillation.

Afterwards the sexes seem to have been formed in vegetables as in flowers, in addition to the power of solitary reproduction by buds. So in animals the aphis is propagated both by solitary reproduction as in spring, or by sexual generation as in autumn; then the vegetable sexes began to exist in separate plants, as in the classes monoecia and dioecia, or both of them in the same plant also, as in the class polygamia; but the larger and more perfect animals are now propagated by sexual reproduction only, which seems to have been the chef-d'oeuvre, or capital work of nature; as appears by the wonderful transformations of leaf-eating caterpillars into honey-eating moths and butterflies, apparently for the sole purpose of the formation of sexual organs, as in the silk-worm, which takes no food after its transformation, but propagates its species and dies.

III. _Recapitulation._

The microscopic productions of spontaneous vitality, and the next most inferior kinds of vegetables and animals, propagate by solitary generation only; as the buds and bulbs raised immediately from seeds, the lycoperdon tuber, with probably many other fungi, and the polypus, volvox, and taenia. Those of the next order propagate both by solitary and sexual reproduction, as those buds and bulbs which produce flowers as well as other buds or bulbs; and the aphis, and probably many other insects. Whence it appears, that many of those vegetables and animals, which are produced by solitary generation, gradually become more perfect, and at length produce a sexual progeny.

A third order of organic nature consists of hermaphrodite vegetables and animals, as in those flowers which have anthers and stigmas in the same corol; and in many insects, as leeches, snails, and worms; and perhaps all those reptiles which have no bones, according to the observation of M. Poupart, who thinks, that the number of hermaphrodite animals exceeds that of those which are divided into sexes; Mem. de l'Acad. des Sciences. These hermaphrodite insects I suspect _to_ be incapable of impregnating themselves for reasons mentioned in Zoonomia, Sect. XXXIX. 6. 2.

And, lastly, the most perfect orders of animals are propagated by sexual intercourse only; which, however, does not extend to vegetables, as all those raised from seed produce some generations of buds or bulbs, previous to their producing flowers, as occurs not only in trees, but also in the annual plants. Thus three or four joints of wheat grow upon each other, before that which produces a flower; which joints are all separate plants growing over each other, like the buds of trees, previous to the uppermost; though this happens in a few months in annual plants, which requires as many years in the successive buds of trees; as is further explained in Phytologia, Sect. IX. 3. 1.

IV. _Conclusion._

Where climate is favourable, and salubrious food plentiful, there is reason to believe, that the races of animals perpetually improve by reproduction. The smallest microscopic animals become larger ones in a short time, probably by successive reproductions, as is so distinctly seen in the buds of seedling apple-trees, and in the bulbs of tulips raised from seed; both which die annually, and leave behind them one or many, which are more perfect than themselves, till they produce a sexual progeny, or flowers. To which may be added, the rapid improvement of our domesticated dogs, horses, rabbits, pigeons, which improve in size, or in swiftness, or in the sagacity of the sense of smell, or in colour, or other properties, by sexual reproduction.

The great Linneus having perceived the changes produced in the vegetable world by sexual reproduction, has supposed that not more than about sixty plants were at first created, and that all the others have been formed by their solitary or sexual reproductions; and adds, Suadent haec Creatoris leges a simplicibus ad composita; Gen. Plant. preface to the natural orders, and Amenit. Acad. VI. 279. This mode of reasoning may be extended to the most simple productions of spontaneous vitality.

There is one curious circumstance of animal life analogous in some degree to this wonderful power of reproduction; which is seen in the propagation of some contagious diseases. Thus one grain of variolous matter, inserted by inoculation, shall in about seven days stimulate the system into unnatural action; which in about seven days more produces ten thousand times the quantity of a similar material thrown out on the skin in pustules!

The mystery of reproduction, which alone distinguishes organic life from mechanic or chemic action, is yet wrapt in darkness. During the decomposition of organic bodies, where there exists a due degree of warmth with moisture, new microscopic animals of the most minute kind are produced; and these possess the wonderful power of reproduction, or of producing animals similar to themselves in their general structure, but with frequent additional improvements; which the preceding parent might in some measure have acquired by his habits of life or accidental situation.

But it may appear too bold in the present state of our knowledge on this subject, to suppose that all vegetables and animals now existing were originally derived from the smallest microscopic ones, formed by spontaneous vitality? and that they have by innumerable reproductions, during innumerable centuries of time, gradually acquired the size, strength, and excellence of form and faculties, which they now possess? and that such amazing powers were originally impressed on matter and spirit by the great Parent of Parents! Cause of Causes! Ens Entium!

ADDITIONAL NOTES. IX.

STORGE.

And Heaven-born STORGE weaves the social chain.

## CANTO II. l. 92.

The Greek word Storge is used for the affection of parents to children; which was also visibly represented by the Stork or Pelican feeding her young with blood taken from her own wounded bosom. A number of Pelicans form a semicircle in shallow parts of the sea near the coast, standing on their long legs; and thus including a shoal of small fish, they gradually approach the shore; and seizing the fish as they advance, receive them into a pouch under their throats; and bringing them to land regurgitate them for the use of their young, or for their future support. Adanson, Voyage to Senegal. In this country the parent Pigeons both male and female swallow the grain or other seeds, which they collect for their young, and bring it up mixed with a kind of milk from their stomachs, with their bills inserted into the mouths of the young doves. J. Hunter's works.

The affection of the parent to the young in experienced mothers may be in part owing to their having been relieved by them from the burden of their milk; but it is difficult to understand, how this affection commences in those mothers of the bestial world, who have not experienced this relief from the sucking of their offspring; and still more so to understand how female birds were at first induced to incubate their eggs for many weeks; and lastly how caterpillars, as of the silk-worm, are induced to cover themselves with a well-woven house of silk before their transformation.

These as well as many other animal facts, which are difficult to account for, have been referred to an inexplicable instinct; which is supposed to preclude any further investigation: but as animals seem to have undergone great changes, as well as the inanimate parts of the earth, and are probably still in a state of gradual improvement; it is not unreasonable to conclude, that some of these actions both of large animals and of insects, may have been acquired in a state preceding their present one; and have been derived from the parents to their offspring by imitation, or other kind of tradition; thus the eggs of the crocodile are at this day hatched by the warmth of the sun in Egypt; and the eggs of innumerable insects, and the spawn of fish, and of frogs, in this climate are hatched by the vernal warmth: this might be the case of birds in warm climates, in their early state of existence; and experience might have taught them to incubate their eggs, as they became more perfect animals, or removed themselves into colder climates: thus the ostrich is said to sit upon its eggs only in the night in warm situations, and both day and night in colder ones.

This love of the mother in quadrupeds to the offspring, whom she licks and cleans, is so allied to the pleasure of the taste or palate, that nature seems to have had a great escape in the parent quadruped not devouring her offspring. Bitches, and cats, and sows, eat the placenta; and if a dead offspring occurs, I am told, that also is sometimes eaten, and yet the living offspring is spared; and by that nice distinction the progenies of those animals are saved from destruction!

"Certior factus sum a viro rebus antiquissimis docto, quod legitur in Berosi operibus homines ante diluvium mulierum puerperarum placentam edidisse, quasi cibum delicatum in epulis luxuriosis; et quod hoc nefandissimo crimine movebatur Deus diluvio submergere terrarum incolas." ANON.

It may be finally concluded, that this affection from the parent to the progeny existed before animals were divided into sexes, and produced the beginning of sympathetic society, the source of which may perhaps be thus well accounted for; whenever the glandular system is stimulated into greater natural action within certain limits, an addition of pleasure is produced along with the increased secretion; this pleasure arising from the activity of the system is supposed to constitute the happiness of existence, in contradistinction to the ennui or taedium vitae; as shown in Zoonomia, Sect. XXXIII. 1.

Hence the secretion of nutritious juices occasioned by the stimulus of an embryon or egg in the womb gives pleasure to the parent for a length of time; whence by association a similar pleasure may be occasioned to the parent by seeing and touching the egg or fetus after its birth; and in lactescent animals an additional pleasure is produced by the new secretion of milk, as well as by its emission into the sucking lips of the infant. This appears to be one of the great secrets of Nature, one of those fine, almost invisible cords, which have bound one animal to another.