186 A Vaper proving that the Bmlryos of the Seeds 



halved, which plainly evinces how solid they are. They caiuiot be 

 £ir; for, if placed in the air-pump, and a vacuum formed round 

 tliem, it has not ike smallest effect on them ; whereas, place a 

 real air-vessel, or rather a water plant with bubles of air in it, 

 and the moment the vacuum is produced, all the bubbles sivcll 

 and burst. But there are certainly no regular air-vessels, except 

 in water or some water plants, though many air-bubbles ac- 

 company the sap. If they were not seeds, would they not ap- 

 pear at all times, and not be confined to the season preceding 

 the flowering of plants P whereas they are rarely seen but at 

 this time, except in those vegetables that flower twice, or for a 

 long space of time. A few strayed on seed may, however, be 

 found, but not in any quantity. Neither can they be air sjir- 

 roiinded with the h-dxk juices (as they sometimes appear in the 

 firs), because thev are really solid, and because in many trees 

 they are so far removed from the inner hark vessels as to have 

 no communication whatever with them. In the sempervivum 

 tribe, the seeds are all in the alburnum vessels betweea two 

 rinds, while the inner bark vessels, containing the bark juice?, 

 are fixed in the interior lelweeii the second rind and the wood, 

 and cannot therefore approach the seeds. How admirably is this 

 shown in a specimen of the plant ! how plain and decisive is its 

 effect on the mind ! But drawings always leave a doubt behind. 

 This situation of the albiu-num is totally different from that of 

 any otiier plant I am acquainted with, and only I believe to be 

 found in the seifipervivums. 



I may be thought to have made too many objections, where 

 the two first were all sufficieiit ; but I might have added many 

 more, to show how perfect the evidence is, since the vessel of 

 impregnation passing through the seed, as it is always found in 

 the flower, is a corroboration not a little powerful. It is above 

 four seasons since I have pursued this discovery in every mode 

 diligence could suggest ; and I think I may now without fear 

 present it to the public as an absolute fact . Malpighi gave a 

 specimen of the alburnum vessel ; but, not viewing it in the pro- 

 per season, did not see tlicic balls: he took however the inter- 

 vening and smaller ones for air-vessels, (those which I suppose 

 to be tlie powder of the pollen), and the middle vessels which con- 

 tain the seeds (see fig. 1, Plate IV.) he called absorbent vessels, 

 but designated them no further. But why should they not 

 be the embryo of the seeds ? We are now well assured that 

 the bulbo2is roots form the flower in the root, and take in their 

 seeds in the same place. If one set of plants can receive their 

 seeds iliei-e, why should not all ? It requires but cutting a hy- 

 acinth a month before blowing, and all its seeds will be seen 

 jnoui'.ting to the top of the root to enter the flower j but it must 



be 



