88 SCIENCE PROGRESS. 



have done so because this was the terminology of the period 

 in the history of Botany whi6h we are considering. This 

 mode of regarding them had come down from Aristotle, 1 

 who defines " the parts of plants as organs, 2 though quite 

 simple ones ; thus the leaf is the covering of the pericarp, 

 the pericarp of' the fruit ; the roots are the analogues of a 

 mouth, for both absorb nourishment": and again, :J "the 

 nature of plants being stable, there are not many kinds of 

 heteromerous parts ; in the few kinds of work, there is use 

 for but few organs ; wherefore they are to be considered 

 with regard to their form ". That is, all the parts of plants 

 were considered primarily from the physiological point of 

 view of their function ; analogies had been drawn between 

 them, but not homologies. Some indication of a morpho- 

 logical conception of them — that is, of their nature apart 

 from their function — is to be found in the writings of Theo- 

 phrastus of Eresus ; 4 but no real progress was made in this 

 direction until late in the seventeenth century, when Joachim 

 Jung, a philosopher, sometime Professor of Logic, Physics 

 and Metaphysics, and ultimately Rector of the Johanneum 

 in Hamburg, wrote his remarkable botanical treatises, 5 in 



1 Aristotle's work on plants (6eu>pia. 7repl <pvrCov) is lost, though a 

 treatise, De Plantis, is generally included in editions of his works, of which 

 treatise Whewell says {Hist. Induct. Sciences, iii.) that it is "an imposture 

 of the middle ages, full of errors and absurdities": but his extant writings 

 contain numerous references to plants : all these passages have been col- 

 lected by Wimmer under the title " Phytologise Aristotelicae Fiagmenta" 

 (1838), of which Meyer gives a translation in the first volume of his 

 Geschichte der Botanik, 1854. 



2 De Anima, ii., cap. i. 



3 De Partibus Animalium, ii., cap. x. 

 1 Historia Plantarum, lib. i., cap. ii. 



5 They were not published until after his death, when they were issued 

 by his pupils, Fogel and Vagetius. The most important is the Isagoge 

 Phytoscopica, 1678. Some of his definitions are of sufficient interest to 

 warrant quotation ; I quote from Albrecht's edition of the collected works 

 {Opuscula Botanico-Physica, Coburg, 1747). 



" Planta proprie dicta duabus constat partibus, radice et superficie 

 sive parte superna." 



" Radix est pars inferior quae intra corpus solidius quod plantar sedem 

 praebet, abdita, et alimento attrahendo destinata est. Pars superna est, 



