A birth or production of a living being, degenerating from the proper and usual disposition of parts in the species to which it belongs; as, when there are too many members, or too few; or some of them are extravagantly out of proportion, either on the side of defect or excess, - is generally denominated a monster.

F. Malebranche accounts for the production of monsters in the animal world in the following manner: - "The Creator has estabished such a communication between the several parts of his creation, that we are naturally led to imitate one another, i. e. to have a disposition to do the same things, and assume the same manners, with those about which we converse; we have also certain natural dispositions, which incline us to compassion as well as imitation. Of these things most men are sensible, and therefore they need not be proved. The animal spirits, then, are not only naturally carried into the respective parts of the body to perform the same actions and the same motions which we see others do, but also to receive in some manner their wounds, and take part in their sufferings.

"Experience tells us, that when we look attentively on any person severely beaten, or that has a large wound, ulcer, or the like, the spirits immediately flow into those parts of our bodies which answer to those we see suffer in the other; unless their course be stopped from some other principle. This flux of spirits is very sensible in persons of delicate constitutions, who frequently shudder, and find a kind of trembling in the body on these occasions; and this sympathy in bodies produces compassion in the mind.

" Now it must be observed, that the view of a wound, etc. affects the person who views it the more strongly and sensibly, as the person is more weak and delicate; the spirits making a stronger impression on the fibres of a delicate body, than in those of a robust one. Thus, strong and vigorous men, etc. see an execution without much concern, while women, etc. are struck with pity and horror. As to children that are unborn, the fibres of their flesh being incomparably finer than those in women, the course of the animal spirits must necessarily produce much greater alterations.

"These things being laid down, monsters are easily accounted for. Suppose, for instance, a child to be born a fool, and also with its legs and arms broken in the same manner as those are of criminals executed; the phenomena may be accounted for thus: Every stroke given to the poor man struck forcibly the imagination of the mother, and, by a kind of counter-stroke, the tender and delicate brain of the child. Now, though the fibres of the woman's brain were strongly shaken by the violent flux of animal spirits on this occasion, yet they had strength and consistence enough to prevent an entire disorder; whereas the fibres of the child's brain, being unable to bear the shock of those spirits, were quite ruined, and the ravage was great enough to deprive him of reason all his lifetime.

"Again, the view of an execution frightening the mother, the violent course of the animal spirits was directed forcibly from the brain to all those parts of the body corresponding to the suffering parts of the criminal. and the same thing must happen in the child But as the bones were strong enough to resist the impulse of those spirits, they were not damaged; and yet the rapid course of these spirits could easily over-power and break the tender and delicate fibres of the bones of the child; the bones being the last parts of the body that are formed, and bavins: a very slender consistence, while the child is yet in the womb."

To this it may here be added, that had the mother determined the course of these spirits towards some other part of her body, by tickling or scratching herself vehemently, the child would not in all probability have had its bones broken; but the part answering that to which the motion of the spirits was determined, would have been the sufferer. Hence appears the reason why women, in the time of gestation, seeing persons, etc. marked in such a manner in the face, impress the same mark on the same parts of the child; and why, upon rubbing some other part of the body when startled at the sight of any thing, or agitated with any extraordinary passion, the mark or impression is fixed on that hidden part, rather than on the face of the child. From the principles here laid down, most, if not all, of the phenomena of monsters, may be easily accounted for.

Various other theories have been formed by different philosophers and phisiologists. But, after all, it must be confessed that we seem as yet to be very little acquainted with nature in her numerous variations. .

Monsters are more common and more extraordinary in the vegetable than in the animal kingdom, because the different juices are more easily deranged and confounded together. Leaves are often seen, from the internal part of which other leaves spring forth; and it is not uncommon to see flowers of the ranunculus, from the middle of which issues a stalk bearing another flower. M. Bonnet informs us, that in certain warm and rainy years he has frequently met with monsters of this kind in rose-trees. This observer saw a rose, from the centre of which issued a square stalk of a whitish colour, tender, and without prickles, which at its top bore two flower-buds opposite to each other, and totally destitute of a calix; a little above the buds issued a petal of a very irregular shape. Upon the prickly stalk which supported the rose, a leaf was observed which had the shape of trefoil, together with a broad flat pedicle. In the Memoirs of the Academy of Sciences, for 1707, p. 448, mention is made of a rose, from the centre of the leaves of which.issued a rose-branch two or three inches Ions;, and furnished with leaves. See the same Memoirs for 1724, p. 20, and for 1749, p. 44. In the Memoirs for 1755, a very singular instance is mentioned of a monstrosity observed by M. Duhamel, in an apple-tree ingrafted with clay. At the place of the insertion there appeared a bud, which produced a stalk and some leaves; the stalk and the pedicle of the leaves were of a pulpy substance, and had the most perfect resemblance both in taste and small to the pulp of a green apple.

An extraordinary chamamelum is mentioned in the Acta Helvetica. M. Bonnet, in his Recherches sur l'Usage des Feu-dies, mentions likewise some monstrous productions which have been found in fruits with kernels, analogous in their nature to those which occur in the flowers of the ranunculus and of the rose-tree. He has seen a pear, from the eye of which issued a tuft of thirteen or fourteen leaves, very well shaped, and many of them of the natural size. He has seen another pear which gave rise to a ligneous and knotty stalk, on which grew another pear somewhat larger than the first. The stalk had probably flourished, and the fruit had formed. The lilium album polyanthos, observed some years ago at Breslaw, which bore on its top a bundle of flowers, consisting of one hundred and two lilies, all of the common shape, is well-known. M. Regnier has mentioned some individuals monstrous with respect to the flower, in the Journal de Physique et d'Histoire Naturelle, for November, 1785. He has likewise mentioned a monstrous tulip, which is seen in the gardens of some amateurs; juniper berries with horns; a balsamine with three spurs, etc.