ON GUANO. 85 



necessary, precisely analogous to the excretions of the animal frame. 

 I will attempt very briefly to show, that this view, if correct, is of 

 some importance, both to agriculture and to horticulture. Mr. A. A. 

 Hayes, of Boxbury, in a beautiful, simple, and, I believe, original 

 experiment, before the Chemical Society of Boston, proved the exist- 

 ence of phosphoric acid (probably combined in several seeds), by 

 immersing sections of them in weak solutions of sulphate or acetate 

 of copper; in whatever part of the seed phosphoric acid existed, on 

 that part was deposited a precipitate of phosphate of copper ; this 

 was particularly evident in the seeds of India corn. A certain quan- 

 tity of phosphoric acid, or phosphates, is therefore necessary to the 

 existence of these seeds : and that part of the plant (probably the 

 flower) destined to perform the functions of preparing the juices for 

 these seeds, must go on exerting its utmost powers in selecting and 

 rejecting, until the requisite quantity of phosphates and other ingre- 

 dients for the seed are obtained. Now the phosphates in most soils 

 exist in extremely minute quantities ; therefore, those plants and 

 flowers whose seeds require them, must extract large portions of food 

 from the soil before they can select the amount of phosphate neces- 

 sary for the perfections of their seed ; and probably, only as many 

 seeds arrive'at maturity as the plant can procure phosphates to com- 

 plete ; the remainder, embryos of which are always formed in abund- 

 ance, are abortive — that is, never come to perfection. The same line 

 of reasoning, of course, applies to the other necessary ingredients of 

 seeds. If, therefore, we present to a plant food containing an abundant 

 supply of these ingredients, it seems reasonable to suppose, that we 

 shall produce more seeds, or rather that more of the embryo seeds 

 will be perfected. Now, the chemical analysis of Guano, shows that 

 it contains, in abundance, most of the necessary ingredients of plants 

 and seeds, the nitrogen of its ammonia being absolutely requisite for 

 the cellular, vascular, and other parts of the stem and leaves, and its 

 phosphoric acid, as well as its nitrogen, for the seeds; and if future 

 experience should confirm what I have thus stated as an opinion, 

 that the flowers of plants manured with Guano become smaller, it 

 may be accounted for on the assumption, that as there are presented 

 to the plant these ingredients in abundance, particularly those neces- 

 sary for the seed, the flower and its glands, whose office it is to 

 prepare the latter, have less work to perform, less food to analyze, less 



