Physiology, in the present day, being more enlightened, and consequently but little credulous in the matter of spon- taneous organizations, and above all of organizations formed by the hand and at the will of man ; convinced, moreover, by observation, that all organized beings result, by tissular exten- sion, from a parent similar to themselves, and which alone has received from nature the power of reproduction ; this physiology, exacting but little, does not demand from phy- sics and synthetical chemistry, unaided by the living labora- tories of which we have just spoken, the construction of an Acarus, which is an animal almost as complicated as one of the Mammifera, but only that of a single muscous globule ofProtosphteria, endowed, let it be understood, with the pro- perties or attributes of organic life, viz absorption, assimila- tion, and the reproduction of its species.

This simple globule, though, in the scale of organization, infinitely below the Acarus of Mr Cross, would be more than sufficient to excite, in the highest degree, the admiration of physiologists and philosophers, or probably might still give rise to fresh doubts.

In producing his animal, Mr Cross is far from having had the merit of priority of invention, but he has at least that of fixing most accurately, the object of his creation, in designa- ting it by the name of Acarus and in shewing us its nature.

It is to be regretted, that the first production of a source so new and unlooked for, should have been one of the ugliest forms of the animal creation.

But let us wait, since this is but a beginning.