A. DeCandolle on the Life and Writings ofVaucher. 163 



By the expression, " Physiological History of Plants," M. 

 Vaucher meant the detailed analysis of the phenomena of 

 vegetable life ; not of any one plant, regarded as similar in 

 general respects to all others, but of a certain species in par- 

 ticular, or of a certain agglomeration of nearly allied species, 

 forming the same section or the same genus. He passes by 

 the general and ordinary questions of physiology, — absorption 

 by the roots, the ascension of the sap, evaporation by the leaves, 

 the modification of the juices by the atmosphere, the forma- 

 tion of the organs by the nutritive juices, the mode of pene- 

 tration of the pollen, &c. &c. He prefers studying each plant 

 in detail in the intimate relations of the different organs and 

 the functions of these organs. He describes what we may call 

 the habits of plants, by analogy with the habits of animals. 

 In this manner of considering the subject, M. Vaucher thought 

 he should be original, and should lay the essential founda- 

 tions of an edifice as yet unerected. In fact, the publication 

 of a considerable work with this particular aim is quite a new 

 thing in science; nevertheless we must not forget, and M. 

 Vaucher himself mentions this, that other naturalists, for 

 example, Conrad Sprengel, Duhamel and Cassini, have pub- 

 lished some partial observations of the same kind on fecun- 

 dation, on the development of the ligneous species, and on the 

 vital phenomena of certain families. All complete mono- 

 graphs, all treatises on cultivation, speak of the succession of 

 phenomena presented by certain plants. The merit of M. 

 Vaucher consists in his desire to extend this kind of observa- 

 tion to an infinity of vegetables which have not yet been suf- 

 ficiently studied. 



The following is the method followed by the author. He 

 enumerates the families and the genera in the order of the 

 works of M. DeCandolle, translates into French the botanic 

 characters expressed in Latin in the ' Prodromus/ and, for the 

 families not yet included in that work, consults the best authors 

 on descriptive botany. Having stated the characters founded 

 on the presence, the situation, and form of the organs, he de- 

 tails his own observations in a physiological point of view. 

 These are sometimes facts relative to the disposition of the 

 leaves in the buds, the varying direction of the peduncles or of 

 the branches, and the development of bulbs and of suckers ; 



already given me so many proofs, this last offering of a heart which has 

 always tenderly loved you, and has entertained the highest hopes of you. 



"J. P. E. Vaucher." 

 A few hours after the death of the author, an affectionate letter in the 

 king's handwriting came from Turin announcing the receipt of the book, 

 and also a portrait of the king sent by his orders. 



M 2 



