'Without vision the people perish' and the very breath of life of science is drawn, and can only be drawn, from that very small band of prophets who from time to time, during the ages, have provided the great generalizations and the great ideals. In this light let us examine the work of Theophrastus. In the absence of any adequate system of classification, almost all botany until the seventeenth century consisted mainly of descriptions of species. To describe accurately a leaf or a root in the language in ordinary use would often take pages. Modern botanists have invented an elaborate terminology which, however hideous to eye and ear, has the crowning merit of helping to abbreviate scientific literature. Botanical writers previous to the seventeenth century were substantially without this special mode of expression. It is partly to this lack that we owe the persistent attempts throughout the centuries to represent plants pictorially in herbals, manuscript and printed, and thus the possibility of an adequate history of plant illustration. Theophrastus seems to have felt acutely the need of botanical terms, and there are cases in which he seeks to give a special technical meaning to words in more or less current use. Among such words are _carpos_ = fruit, _pericarpion_ = seed vessel = pericarp, and _metra_, the word used by him for the central core of any stem whether formed of wood, pith, or other substance. It is from the usage of Theophrastus that the exact definition of fruit and pericarp has come down to us.[18] We may easily discern also the purpose for which he introduces into botany the term _metra_, a word meaning primarily the _womb_, and the vacancy in the Greek language which it was made to fill. '_Metra_,' he says, 'is that which is in the middle of the wood, being third in order from the bark and [thus] like to the marrow in bones. Some call it the _heart_ (καρδιαν {kardian}), others the _inside_ (εντεριωνην {enteriônên}), yet others call only the innermost part of the metra itself the heart, while others again call this _marrow_.'[19] He is thus inventing a word to cover all the different kinds of core and importing it from another study. This is the method of modern scientific nomenclature which hardly existed for botanists even as late as the sixteenth century of our era. The real foundations of our modern nomenclature were laid in the later sixteenth and in the seventeenth century by Cesalpino and Joachim Jung. [18] It is possible that Theophrastus derived the word pericarp from Aristotle. Cp. _De anima_, ii. 1, 412 b 2. In the passage το φυλλον περικαρπιου σκεπασμα, το δε περικαρπιον καρπου {to phyllon perikarpiou skepasma, to de perikarpion karpou}, in the _De anima_ the word does not, however, seem to have the full technical force that Theophrastus gives to it. [19] _Historia plantarum_, i. 2, vi.