SEVENTEENTH AND EIGHTEENTH CENTURIES 1 93 



belong to the reproductive system. The plant is composed of several layers: 

 bark, liber, wood, pith; of these the pith is the innermost and thus corre- 

 sponds to the intestines of animals and is physiologically the most important. 

 He is at much pains to discover which part of the plant corresponds to the 

 heart in animals — we have previously pointed out (Part I, p. 1 13) the great 

 importance which Cesalpino attaches to the heart as the centre of the body 

 and of life. Finally, the plant's centre of life is found to be the collar of the 

 root — the place where the stem and the root system join. Thence extend 

 the vessels of the plant, of which the lacteal vessels especially are observed 

 and compared with the veins in animals. Propagation by means of cuttings 

 shows, however, that the central point of the plant is not as absolute as that 

 of the animal; with true Aristotelean terminology it is maintained that this 

 central point "actu" (actually) is in the root-collar, but "potentia" (po- 

 tentially) can be everywhere. Cesalpino, moreover, is particularly interested 

 in the fruits of plants, in which he sees the equivalent of the animal embryo; 

 the function of the leaves is to protect the fruits, and the flower-petals are 

 modified foils — an idea which was later adopted by Goethe. But Cesalpino 

 does not admit the existence of sex in plants: the fruit is formed from buds 

 and these again are produced out of the pith and the liber; the pith, which is 

 the most vital part of the plant, provides the actual ovule, and the liber gives 

 rise to the flower-leaf. Different kinds of fruits are carefully analysed and 

 the plants are classified in accordance therewith, though the traditional 

 division into trees, shrubs, half-shrubs, and herbs is retained as the main 

 division. These four categories are then divided in their turn, according to 

 the nature of the fruit, into a number of subdivisions. Cesalpino, however, 

 like Aristotle, makes no summary of his system, not even in the form of 

 chapter headings; nor is there any special systematic nomenclature. The 

 mulberry-tree, the hazel-bush, and other fruit-trees are thus described each 

 by itself; nevertheless, there sometimes occur divisions into lower categories 

 than those named: of the carrot. Caucus, for instance, three forms are men- 

 tioned, Creticus, Montanus, Campestris, a division which has the character 

 of a determination of species, or rather of variety. Nevertheless, these and 

 other categories occurring in Cesalpino are not sharply defined; he was un- 

 doubtedly more concerned with anatomical and physiological than with 

 systematic problems. 



Cesalpino's system, in spite of its deficiencies, is the first to have been 

 really based on the comparative study of forms; in this connexion Linnasus, 

 who made a summary of it, expresses the opinion that Cesalpino is the first 

 to lay down a definite basis for plant classification. In later times, however, 

 this basis has been regarded as artificial, since it rests merely upon the con- 

 sideration of one single organ, and in contrast thereto have been adduced 

 contributions to a natural system of classification made by certain of the old. 



