236 Phytotomy founded [BOOK n. 



part of it, he says, the cuticle, consists of utricles or little sacs 

 arranged in horizontal rows ; these die in time and decay, some- 

 times forming a dry epidermis. On the removal of the epidermis, 

 layer after layer of woody fibre is disclosed, and these layers, 

 usually forming reticulations and lying one on another, follow the 

 longitudinal direction of the stem. These fibrous bundles are 

 composed of numerous fibres, and each single fibre of tubes 

 which open into one another (' quaelibet fibra insignis fistulis 

 invicem hiantibus constat') and so on. The interspaces of the 

 network are filled with roundish tubes, which usually have a 

 horizontal direction towards the wood. If the rind is removed 

 the wood appears, chiefly composed of elongated fibres and 

 tubes, and consisting of rings or vesicles open towards one 

 another and arranged in longitudinal rows. The fibres also of 

 the wood do not run parallel to one another, but allow a net- 

 work of angular anastomosing spaces to be formed between 

 them, the larger of which are filled with bundles of tubes, which 

 run from the rind through these interspaces to the pith, etc., etc. 

 Between the fibrous and fistulose bundles of the wood lie the 

 spiral tubes ('spirales fistulae'), smaller in number but of larger 

 size, so that in cross sections of the stem they appear with open 

 orifices. They lie in different positions, but the majority in 

 concentric circles. He says that in the course of ten years' . 

 examination (from 1661 therefore) he found these spiral tubes 

 in all plants, and it may be added here that Grew in the intro- 

 duction to his book expressly concedes the priority in this 

 discovery to Malpighi ; but Malpighi's ideas on the subject of 

 these tubes are extremely indistinct 1 , and this gave occasion to 



1 We read at p. 3 : ' Componuntur expositae fistulae (spirales) zona 

 tenui et pellucida, velut argentei colons, lamina parum lata, quae spiraliter 

 locata et extremis lateribus unita tubum interius et exterius aliquantulum 

 asperum efficit ; quin et avulsa zona capites seu extreme trachearum turn 

 plantarum turn insectorum non in tot disparates annulos resolvitur, tit 

 in perfectorum trachea accidit ; sed unica zona in longum soluta et extensa 

 extrahitur.' 



