two of a sort, one corresponding to the other.

DOUBLE Children, Double Cats, Double Pearls, &c. Instances of these are frequent in the Philosop. Tranf. and elsewhere. See MONSTER.

Sir John Floyer, in the fame Transactions, giving an account of a double turkey, furnishes some reflections on the production of double animals in general. Two turkeys, he relates, were taken out of an egg of the common size, when the rest were all hatched, which grew together, by the flesh of the breast-bone, but in all other parts were distinct. They seemed less than the ordinary size, as wanting bulk, nutriment, and room for their growth; which latter, too, was apparently the occasion of their cohesion. For having two distinct cavities in their bodies, and two hearts, they must have arisen from two cicatriculae; and, consequently, the egg had two yolks; which is no uncommon accident. He mentions a dried double chicken in his possession, which, though it had four legs, four wings, &c. had but one cavity in the body, one heart, and one head; and, consequently, was produced from one cicatricula.

So, Paracæus mentions a double infant, with only one heart, in which case, the original or stamen of the infant was one, and the vessels regular; only, the nerves and arteries towards the extremities dividing into more branches than ordinary, produced double parts.

The same is the case in the double flowers of plants, occasioned by the richness of the soil. So it is in the eggs of quadrupeds, &c.

There are, therefore, two reasons of duplicity in embryos: 1. The conjoining or connection of two perfect animals; and 2. An extraordinary division and ramification of the original vessels, nerves, arteries, &c.