On ihe Plnjiiology of Vegetal les. 131 



transversale est une lame plate qui m'a presente line ellipse, 

 on quekjuefois trois filets reniiis par utie membrane ; jamais 

 je n'ai peu appercevoir i'ouverture d'un tube^ comme plusieurs 

 auteurs I'ont avaiicee." 



If there is no passage in these spiral vessels, they cannot carry 

 the sap; and it must pass through the vessels, or rather voids, 

 which so plainlv appear in the wood at fig. 5 and 6. Indeed the 

 French authors are ail of this opinion ; and oi dissectors I know 

 but Mr. Knight, who turns over the office to these diminutive 

 twisted vessels. Du Hamel looked on the s])irals as containing 

 air only: but they have a much more important office, and are 

 certainly the universal cause of motion to plants, resembling the 

 animal muscles in every respect, and possessii7g, like them, that 

 vis insiia which is a proof of their identity impossible to deny. 



If, therefore, the account given of the figure of plants do not 

 agree in the interior, or answer to their appearance, when given 

 by my opponents, though adduced by them as exact, — brought 

 forward by themselves ; How should my drawings agree with 

 their accounts P when their accounts do not agree with their own 

 drawings ; for as a void will do as well as p. vessel, the reason 

 against the flow of the sap in them vanishes. And as the wreaths 

 of fiowersdisplay themselves coming out of the seed in December, 

 Ijefore tl'.e seed has passed up the stem, those flowers cannot be 

 formed in the flower-bud the following May. And as the seeds 

 which contain these shoots appear in quantities in November, and 

 can be made to increase their premature shoots l-)efore they rise 

 in the stem; thev cainiot be produced in the following July and 

 August in tiie seed-vessel at the top of the plants. 

 I am, sir, 



Your obliged servant, 

 Exeter, Nov. 'i, 1316. AgnES IbbuTSON. 



Description of the Plate No. 5, [see PI. II,] 



Fig. 1 . The shoot mentioned by Mr. Baker. 



Fig. 2. The exterior of the seed or husks. 



Fig. 3. The figure of the embryo of the bean, with the seed a a 



joined to it. 

 Fig, 4, Piece of the wood as I see it with the flowers at mm. 

 Fig. 5, Piece of the wood given by I\Hrbel, without the flowers. 

 Fig. 6. The wood cut horizontailv, given by Grew: sap-vessels 



ddd. 

 Fig. 7. Tiie sap-vessels, showing the s])iral at the top which 



contracts and stretches alternately to let the buds pass. 

 Fig. 8, showitijr the inauticr the wood changes its. figiuc to let 



the budi pais. 



I -J rik'- 



