is deposited during Winter. 315 



experiments of Ingenhousz prove that their action on the 

 air which surrounds them is very essentially different from 

 that of full grown leaves. It is true that buds in many 

 instances will vegetate and produce trees, when a very small 

 portion only of alburnum remains attached to them : but 

 the first efforts of vegetation in such buds are much more 

 feeble than in others to which a larger quantity of alburnum 

 is attached ; and therefore we have, in this case, no grounds 

 to suppose that the leaves derive their lirst nutriment from 

 the crude sap. 



It is also generally admitted, from the experiments of 

 Bonnet and Du tiamc;!, whi'.h I have repeated with the 

 same result, that in the cotyledons of the seed is deposited 

 a quantity of nutrniieal loi the bud, which every seed con- 

 tains ; and though no vessels can be traced* which lead 

 immediately from the cotyledons to the bud or plumula, it 

 is not difficult to point put a more circuitous passage, which 

 is perfectly similar lo that through which 1 conceive 'ne 

 sap to be carried from t£\e leaves to the buds in the subse- 

 quent growth of he tre? ; and I am in possession of many 

 facts to prove th?'. seedlmg trees, in the first stage of their 

 existence, depend entirely on the nutriment afforded by the 

 cotyledons; and that they are greatly mju'ed, and m many 

 instances killed, by beiiig pui to vegetate in rich mould. 



We have much more decisive evidence that Dulbous and 

 tuberous rooted plants contain the riiatter within themselves 

 which subsequently composes their leaves ; for we see them 

 vegetate even in dry rooms on the approach of spring; and 

 many bulbous rooted plants produce their leaves and flowers 

 with nearly the same vigour by the application of water 

 only, as they do when growing in the best mould. But 

 the water in this case, provided that it be perfectly pure, 

 probably affords little or no food to the plant, and acts only 

 by dibsolving the matter prepared and deposited in the pre- 

 ceding year; and hence the root becomes cxliaustcd and 

 spoiled : and Ilassenfratz found that the leaves and flowers 

 and roots of such plants allbrded no more carbon than he 

 had proved to exist in bulbous roots of the same wcjin^ht, 

 whose leaves and fio.wcrs had never expanded. 



As the leaves and flowers of the hyacinth, in the pre- 

 ceding case, derived their matter from the bulb, it appears 

 extremely probable that the blossoms of trees receive their 

 nutriment from the alburiuun, particularly as the blossoms 

 <)f many species precede their leaves : and as the roots of 

 plants become weakened and apparently exhausted, when 

 ♦ Hi-dwig. 



they 



