II. Probably one main cause which so long retarded the work of fixing at the same time the arrangement and the names of plants, was the great number of minute and diversified particulars in the structure of each plant which such a process implied. The stalks, leaves, flowers, and fruits of vegetables, with their appendages, may vary in so many ways, that common language is quite insufficient to express clearly and precisely their resemblances and differences. Hence botany required not only a fixed system of _names_ of plants, but also an artificial system of phrases fitted to _describe_ their parts: not only a _Nomenclature_, but also {272} a _Terminology_. The Terminology was, in fact, an instrument indispensably requisite in giving fixity to the Nomenclature. The recognition of the kinds of plants must depend upon the exact comparison of their resemblances and differences; and to become a part of permanent science, this comparison must be recorded in words. The formation of an exact descriptive language for botany was thus the first step in that systematic construction of the technical language of science, which is one of the main features in the intellectual history of modern times. The ancient botanists, as De Candolle[9\4] says, did not make any attempt to select terms of which the sense was rigorously determined; and each of them employed in his descriptions the words, metaphors, or periphrases which his own genius suggested. In the History of Botany[10\4], I have noticed some of the persons who contributed to this improvement. 'Clusius,' it is there stated, 'first taught botanists to describe well. He introduced exactitude, precision, neatness, elegance, method: he says nothing superfluous; he omits nothing necessary.' This task was further carried on by Jung and Ray[11\4]. In these authors we see the importance which began to be attached to the exact definition of descriptive terms; for example, Ray quotes Jung's definition of _Caulis_, a stalk. [Note 9\4: _Theor. Elem. de Bot._ p. 327.] [Note 10\4: _Hist. Ind. Sc._ b. xvi. c. iii. sect. 3.] [Note 11\4: _Hist. Ind. Sc._ b. xvi. c. iii. sect. 3 (about A.D. 1660).]