in surgery, &c. See Abscess.

IMPOLENCY, or Impotence, in general, denotes want of strength, power, or means to perform anything.

Divines and philosophers distinguish two sorts of impotence; natural, and moral. The first is a want of some physical principle, necessary to an action; or where a being is absolutely defective, or not free and at liberty to act: the second only imports a great difficulty, as a strong habit to the contrary, a violent passion, or the like.

Impotence is, more particularly, used for a natural inability to coition. Impotence with respect to men, is the same as sterility in women; that is, an inability of propagating the species. There are many causes of impotence; as, a natural defect in the organs of generation, which seldom admits of a cure; accidents, or diseases; and in such cases the impotence may, or may not be remedied, according as these are curable or otherwise.

IMPEGNATION, the getting a female with-child. See Pregnancy.

The term impregnation is also used, in pharmacy, for communicating the virtues of one medicine to another, whether by mixture, coction, digestion, &c.

IMPRESSION is applied to the species of objects, which are supposed to make some mark or impression on the senses, the mind, and the memory.

The peripatetics assert, that bodies emit species resembling them, which are conveyed to the common sensillum, and they are rendered intelligible by the active intellect; and when thus spiritualized, are called expressions, or express species, as being expressed from the others.

IMPRESSION also denotes the edition of a book, regarding the mechanical part only; whereas edition, besides this, takes in the care of the editor, who corrected or augmented the copy, adding notes, &c., to render the work more useful.