An essay on the comparative merits of artificial and natural classification, as applied to diseases of the skin ... / [John Paget].

  • Paget, John, 1808-1892.
Date:
1833
Catalogue details

Licence: Public Domain Mark

Credit: An essay on the comparative merits of artificial and natural classification, as applied to diseases of the skin ... / [John Paget]. Source: Wellcome Collection.

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    different relative importance, as to the characters they furnish in the one and in the other. In botany, the organs of reproduc¬ tion serve for the basis of a system ; in zoology, those of assi¬ milation are always preferred. In other sciences, not quite so naturally connected as these, the error becomes still more ob¬ vious ; for we find certain characters prevailing among a num¬ ber of species and genera with such constancy, and drawn from such essential circumstances, that they are directly allowed to be of sufficient importance to constitute a natural family, which the very same characters in certain other genera are so incon¬ stant, and so unessential, as not to suffice even for the establish¬ ment of a species. In the diseases of the skin, if it be not premature to draw illustrations from a subject to which the principles are not yet proved applicable, we might quote the Exanthemata and Psoro- des, as furnishing striking examples of this observation. In the former, the occurrence of a primary fever, and the succession at a certain period of an eruption on the skin, form constant and essential characters. In the latter they would be considered only as incidental and trifling coincidences. This is, however, of no real weight as an objection to the application of natural arrangement to diseases of the skin, since it prevails, even in botany, in the establishment of the different genera of some families. In the Umbelliferce, for example, the generic characters would be insufficient to distinguish the spe¬ cies, even of another family. In reducing diseases, then, to a natural nosological arrange¬ ment, we should say, if we may venture a hasty conjecture on a question of such delicacy and importance, that the characters are important in proportion as they are constant in any one family, and in proportion as the symptoms from which they are derived regard the life of the individual,—as they extend their effects to other parts of the organization, or as they produce con¬ stitutional sympathies,—as they respect the formation of per¬ manent organic changes, as they effect appreciable alteration of form and appearance, as they modify the principles of treat¬ ment, as they affect the sensations of the patient, and as they regard the causes of the disease. The second part of the theory of classification, or the know¬ ledge of the circumstances which might mislead the observer in regard to the true nature of the organs, is one of great import¬ ance. In natural history these circumstances principally regard excesses or deficiences in developement, either congenital, or formed at a later period of existence. They include, also, the changes of form and structure effected by climate, soil, nourish- 4