100 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 54 



were confirmation called for. Hitherto I have conformed to 

 usage, very ancient as well as modern, of writing bark, wood, pith, 

 in just that sequence. It seems natural. It is at least a geo- 

 metrical succession of the terms, and therewithal not inelegant. 

 Even the translators of Theophrastus from Greek into Latin have 

 made him out as having named first the bark, then the wood, and 

 lastly the pith. Unwittingly they committed an inaccuracy, and 

 have misrepresented him; for Theophrastus wrote it thus: bark, 

 pith, wood. This sequence is not geometric, but it is biologic. 

 It would be illogical and awkward, were it not more exactly truthful 

 than the other and merely geometric succession of the terms. As 

 he placed them, the story is told again of how in early stages of 

 development bark and pith are substantially identical. Therefore 

 in their most widely differentiated condition they are next of kin, 

 more nearly related each to the other than either one is to the 

 wood. 



This biologic investigation of the pith led to the detection and 

 segregation of other elements in stem structure; discoveries that 

 are all his own, for he expressly says of these elements that they 

 have no names. He thinks that he can not do better than apply to 

 each the name of some analogous part of the anatomy of animals. 

 The whole fabric of stems he makes out as consisting of what he 

 calls veins, nerves, and flesh. They are new uses of these terms 

 and he defines the botanical use of each, premising first of all that 

 vein and nerve are substantially one, differing scarcely otherwise 

 than as to dimensions, nerves being smaller than veins; adding 

 also that in plants these are simply elongated and do not branch. 

 The universal mark of the fabric which is composed of them is, 

 that it splits, and is not otherwise readily divisible. Flesh has 

 the very different quality of being divisible with equal readiness 

 in all directions, like a lump of earth. ' Here, quite as we had been 

 prepared to expect from his new naming of the pith, and his indi- 

 cating its consanguinity with bark rather than with wood, we see 

 plainly that Theophrastus discovered and distinguished well what 

 in post-Malpighian times we have learned to know as parenchyma 

 ■ and prosenchyma. He is now able to add a new chapter to plaint 

 anatomy, for he can name the elemental constituents of bark, of 

 wood, and of pith. Wood, he says, is composed of nerve and 

 moisture ; although some woods, such as of the palms and of ferula, 

 are of flesh ; such however in mature and dry condition show that 

 the flesh has been partly converted into wood. When he cites 

 ' Hist., Book i, ch. 4. 



