116 OBSERVATIONS ON THE STATE OF THE 



in this case, provided that it be perfectly pure, probably affords little or 

 no food to the plant, and acts only by dissolving the matter prepared and 

 deposited in the preceding year ; and hence the root becomes exhausted 

 and spoiled : and Hassenfratz found that the leaves and flowers and 

 roots of such plants afforded no more carbon than he had proved to exist 

 in bulbous roots of the same weight, whose leaves and flowers had never 

 expanded. 



As the leaves and -flowers of the hyacinth, in the preceding case, 

 derived their matter from the bulb, it appears extremely probable that 

 the blossoms of trees receive their nutriment from the alburnum, particu- 

 larly as the blossoms of many species precede their leaves ; and, as the 

 roots of plants become weakened and apparently exhausted when they 

 have afforded nutriment to a crop of seed, we may silspect that a tree, 

 which has borne much fruit in one season, becomes in a similar way 

 exhausted, and incapable of affording proper nutriment to a crop in the 

 succeeding year. And I am much inclined to believe that were the wood 

 of a tree in this state accurately weighed, it would be found specifically 

 lighter than that of a similar tree, which had not afforded nutriment to 

 fruit or blossoms in the preceding year or years. 



If it be admitted that the substance which enters into the composition 

 of the first leaves in the spring is derived from matter which has under- 

 gone some previous preparation within the plant (and I am at a loss to 

 conceive on what grounds this can be denied, in bulbous and tuberous 

 rooted plants at least), it must also be admitted that the leaves which 

 are generated in the summer derive their substance from a similar 

 source ; and this cannot be conceded without a direct admission of the 

 existence of vegetable circulation, which is denied by so many eminent 

 naturalists. I have not, however, found in their writings a single fact to 

 disprove its existence, nor any great weight in their arguments, except 

 those drawn from two important errors in the admirable works of Hales 

 and Duhamel, which I have noticed in a former memoir. I shall 

 therefore proceed to point out the channels through which I conceive the 

 circulating fluids to pass. 



When a seed is deposited in the ground, or otherwise exposed to a 

 proper degree of heat and moisture and exposure to air, water is 

 absorbed by the cotyledons, and the young radicle or root is emitted- 

 At this period, and in every subsequent stage of the growth of the root> 

 it increases in length by the addition of new parts to its apex, or point, 

 and not by any general distension of its vessels and fibres ; and the 

 experiments of Bonnet and Duhamel leave little grounds of doubt but 



