STATE OF THE SAP IN WINTER. 309 



tkmtter prepared anddepofited in the preceding year ; and hence 

 the root becomes exhau (led and fpoiled: and Haflenfratz found 

 that the leaves and flowers and roots of fuch plants afforded no 

 more carbon than he had proved to exift in bulbous roots of the 

 fame weight, whofe leaves and flowers had never expanded. 



As the leaves and flowers of the hyacinth, in the preceding —and it Is 

 cafe, derived their matter from the bulb, it appears extremely ^f^ewtlm-* 

 probable that the bloflbms of trees receive their nutriment from tain the nutri- 

 the alburnum, particularly as the bloflbms of many fpecies me . nt ^ thc " v 

 precede their leaves : and, as the roots of plants become weak- 

 ened and apparently exhaufted, when they have afforded nutri- 

 ment to a crop of feed, we may fufpect that a tree, which has 

 borne much fruit in one feafon, becomes in a fimilar way 

 exhaufted, and incapable of affording proper nutriment to a crop 

 in the fucceeding year. And I am much inclined to believe 

 that were the wood of a tree in this ftate accurately weighed, 

 it would be found fpecifically lighter than that of a fimiiar tree, 

 which had not afforded nutriment to fruit or bloflbms, in the 

 preceding year, or years. 



If k be admitted that the fubftanee which enters into the The preparation 



corapofition of the firft leaves in the fprine- is derived from /? " u , m " m 

 ' * ° me,nt in the trea 



matter which has undergone fome previous preparation within implies thatthe 

 *he plant, (and I am at a lofs to conceive on what grounds this J ulces circulate » 

 can be denied, in bulbous and tuberous roofed plants at leaft,) 

 it muft alio be admitted that the leaves which are generated in 

 the fummer derive their fubftanee from a fimilar fource; and 

 this cannot be conceded without a direcf admiflion of the 

 •exiftence of vegetable circulation, which is denied by fo many 

 eminent naturalifts. I have not, however, found in their writ- 

 ings a tingle fact to difprove its exiftence, nor any great weight 

 in their arguments, except thofe drawn from two important 

 errors in the admirable works of Hales and Du Hamel, which 

 I have noticed in a former memoir. I (hall therefore proceed 

 to point out the channels, through which I conceive the circu* 

 lating fluids to pafs. 



When a feed is depofi ted in the ground, or other wife expofed Explanation of 

 , ... * t > c - the manner in 



to a proper degree of heat and moilture, and expofure to air, wWc j 1 thejuiox 



water is abforbed by the cotyledons and (he young radicle or of plants circu- 



root is emitted. At this period, and in every fubfequent ftage J^ * c ^ n ^g 



of the growth of the root, it increaies in length by the addition & c . 



of new parts to its apex, or point, and not by any general dif- 



* tend on 



