MONSTER; a birth or production of a living thing degenerating from the proper and usual disposition of parts in the species it belongs to. 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 excels. The word comes from the Latin monstrum, of monstrando, "shewing." Whence also the box wherein relics were anciently kept to be shewn, was called monstrum. Dugdale mentions an inventory of the church of York with this article, Item unum monstrum cum offibus sancti Petri in Beryl, & crucifixo in summitate.

Aristotle defines a monster to be a defect of nature, when acting towards some end, it cannot attain to it, by reason some of its principles are corrupted.

Monsters do not propagate their kind; for which reason some rank mules among the number of monsters; as also hermaphrodites.

Females which bring forth twins, are found most liable to produce monsters. The reason, probably, is owing to this; that though the twins are covered with one common chorion, yet they have each their separate amnios, which, by their contiguity may chance to grow together, and so occasion a confusion or blending of the parts. Hence so many double creatures.

F. Malebranche accounts for the production of monsters in the animal-world, thus: The creator has established such a communication between the several parts of his creation, that we are not only naturally led to imitate one another, i.e. have a disposition to do the same things and assume the same manners with those with whom we converse; but also have certain natural dispositions which incline us to compassion as well as imitation. These things most men feel, and are sensible of; and therefore 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 hath a large wound, ulcer, or the like, the spirits immediately flow into those parts of our body 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 a delicate constitution, 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, &c. wounds 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, vigorous men, &c. see an execution without much concern, while women, &c. are struck with pity and horror. As to children still in their mother's womb, womb, 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, v. gr. a child born a fool, and with all its legs and arms broke in the same manner as those of criminals in some countries are; which case we choose to instance in, because we are told from Paris that such a monster was actually born there, and lived in one of their hospitals 20 years: the cause of this accident, according to the principles laid down, was, that the mother seeing a criminal executed, every stroke given to the poor man, struck forcibly the imagination of the woman; 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 strangely shaken by the violent flux of animal-spirits on this occasion, yet they had strength and confidence 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 the execution frightening the woman, 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 in regard the bones of the mother were strong enough to resist the impulse of those spirits, they were not damaged: And yet the rapid course of these spirits could easily overpower 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 having a very slender confidence while the child is yet in the womb.

To which it may be here 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, &c., marked in such a manner in the face, impresses the same mark on the same parts of the child: and why, upon rubbing some hidden 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, may most, if not all, the phenomena of monsters be easily accounted for.