Volume 1

An introduction to medical literature, including a system of practical nosology, intended as a guide to students, and an assistant to practitioners. Together with detached essays on the study of physic, on classification, on chemical affinities, on animal chemistry, on the blood, on the medical effects of climates, on the circulation, and on palpitation. / By Thomas Young.

  • Thomas Young
Date:
1823
Catalogue details

Licence: Public Domain Mark

Credit: An introduction to medical literature, including a system of practical nosology, intended as a guide to students, and an assistant to practitioners. Together with detached essays on the study of physic, on classification, on chemical affinities, on animal chemistry, on the blood, on the medical effects of climates, on the circulation, and on palpitation. / By Thomas Young. Source: Wellcome Collection.

    56/696 (page 24)
    159. Genera are determined in botany from the agree-~ ment of the parts of fructification. 160. Classes are deduced from the regular agreement of many genera, in the parts which characterize them. 161. An order is a subdivision of a class, intended for convenience. _ 162. Species and genera depend on nature: varieties often on cultivation : classes and orders on a combination of nature and art. [In Dr. Cullen’s opinion, species alone are established by nature; the constitution of genera is an invention of the human mind, which must necessarily be imperfect untill all existing species are known. Synops. proleg. p. xi. Indeed in nosology, the constitution of genera must commonly be in some measure arbitrary. I have endeavoured to arrange them upon the principle of the greatest utility, uniting such species of diseases, as are most conveniently considered together, with respect to their nature and to their cure. ] 163. Habit isa general agreement in growth and appearance. 168. Habit is to be silently consulted in forming genera, but must not and cannot be described. To prefer habit to the more regular characters is folly. 209. 169. No positive rules can be laid down respecting identity of genus. Thus some species may be monopetalous, or monospermous, others of the same genus polypetalous or polyspermous. 170. Few genera are without some cases of accidental deviation. 171. Each genus is commonly characterized by some decided singularity of form. 172—3. Genera thus marked must be kept distinct or united accordingly. 174. The more constant the mark in different species, the better distinction it affords. 175. Different parts are the most constant in different genera; but scarcely any part is ever wholly invariable. 186. A generic character is the definition of a genus, and may be of three kinds, factitious, essential, or natural.