43 8 THE HISTORY OF BIOLOGY 



a universal symmetry, a standard of organization, which is modified in the 

 individual by the same organ's being capable of serving different purposes 

 and the other organs' undergoing corresponding changes. Among these 

 changes he includes especially stunted growth, degeneration, and accretion; 

 in his view a flower with free petals is higher than one with accrete petals — 

 a principle which he applied in his system, though it failed to gain the ac- 

 ceptance of posterity. For the rest, he introduced into his system reforms of 

 lasting value; the difference between vascular and cellular plants was estab- 

 lished by him, as also the contrast between the bole-plants and the higher 

 plants. Further, his classification of the dicotyledons has been largely ac- 

 cepted by subsequent botanists. Otherwise, de Candolle strongly repudiates 

 Lamarck's theory of one single evolutional chain in the organisms, instead 

 associating himself with Linnasus's idea of the natural system's likeness to 

 a map; in fact, his idea of species is not unlike the Linnasan: according to 

 de Candolle, a species is "the sum total of all the individuals which mutually 

 resemble one another more than they resemble others, which are capable by 

 mutual fertilization of producing fertile individuals, and which are multi- 

 plied by generation, so that it is possible by analogy to assume that they 

 have originally sprung from a single individual." Varieties arise, he con- 

 siders, partly through the influence of local conditions of life and partly 

 through hybridization; moreover, there are in certain quarters varieties 

 which must be regarded as constant, like the species, and which should be 

 distinguished from the accidental local varieties. The genus is defined as a 

 collection of species with a striking mutual resemblance in regard to all 

 organs; families and higher categories are given similar definitions. 



Among de Candolle 's other works may be mentioned his Organography, 

 an account of the organic systems of plants, and his Physiologie vegetale, a 

 work of great merit for its time, based on a thorough knowledge of the vital 

 conditions of plants and of chemical and physical processes belonging thereto. 

 We must, however, pass over these works here; as a matter of fact, it is 

 mostly as a reformer and theoretician in the sphere of classification that 

 de Candolle has made his best contribution to the development of biology. 



End lie her' s sysfem 

 The development of plant classification received further impetus through 

 Stephan Ladislaus Endlicher (1805-49). Bo"*^ of wealthy parents at Press- 

 burg, he studied first of all theology, but afterwards devoted himself both 

 to botany and oriental languages. He became professor of botany and head 

 of the botanical gardens in Vienna, acquiring fame for the splendid initiative 

 he took in furthering the development of natural science in Austria, gener- 

 ously contributing towards that end out of his own private purse. He pre- 

 sented his herbarium to the State and published a botanical journal at his 

 own expense. At the same time he made a name for himself as an expert in 



