In order rightly to understand this subject, it is necessary properly to comprehend the nature 

 of vegetable bodies. 



This will be best understood, if we trace downwards the great Chain of Nature ; that is, if 

 we begin with man, next consider quadrupeds, then birds, fishes, reptiles, worms, insects, and 

 lastly, descend to vegetables. 



que probablement il n' a pas fait. II est aussi vraisemblable, que ce qui arrive ici parmi les plantes d'Epinars, arrive plus souvent parmi les 

 Diphytes, et je ne crois pas me tromper, en supposant, que ma plante de Chanvre XCVIII. que j'avois quittee femelle et trouvde male quelque 

 tems apres, a ete' sujette k la meme metamorphose. Nous avons vu en son lieu la meme chose dans les Monophytes, comme dans le Mays et 

 dans la noisette, ou ce changement de sexe est plus concevable, que celui des Diphytes, puisque dans celles-la il peut dependre d'une confusion 

 ou d'une distribution irreguliere de la seve male et femelle et des organes sexuels, qui se trouvent ensemble dans la meme plante, mais dans 

 celles-ci, c est a dire dans les Diphytes, ou chaque plante est pourvue de ses propres vaisseaux et de ses organes sexuels, ce changement devient 

 un enigme du quel j'abondonne I'explication aux Botanistes, que leur metier oblige a instruire le monde la dessiis, Aussi jugeront-ils cette 

 peine tres necessaire, s'ils considerent les consequences importantes, qu'on en peut tirer au sujet de la generation, et que Mr. Linneeus nous a 

 fait entrevoir par sa conjecture. Car ce Savant a soupponne, que le sexe originaire de toutes les plantes etoit celui des Hermaphrodites." 



Spalanzani, a philosopher of the highest character, after numerous experiments on bisexual flowers, where he found that removing the 

 anthers produced always barrenness of the seeds, proceeded upon those plants which staggered Alston. Like that professor, he experienced 

 a contradiction to the general doctrine, but confesses an accident not very uncommon in the unisexual flowers, viz. the occasional production 

 of stamina amongst the females. " It has been observed," says Spalanzani, " by Linnaeus, Haller, Duhamel, and others, that male flowers 

 are not very infrequently found upon female individuals : a root of spinach, of which I shall speak below, furnished me with a remarkable 

 instance; and the hemp in question is subject to the same accident, as I was informed by Mr. Bonnet, in a letter dated August 15, 1778. 

 The letter gave me notice of an experiment which he undertook upon hemp, after I had communicated mine to him. The paragraph to which 

 I allude is the following : " I began this year some experiments upon hemp. I have followed the method which I employed for rearing the 

 insects on plants in solitude. My plants were covered with large tubes of glass, hermetically sealed at the top, and with the bottom sunk in the 

 earth. But fortune did not favour me — instead of a female I had a male plant in one instance, and in another a plant of great expectation, 

 after putting forth many flowers with pistils, produced some with stamina, close to the former, which totally disconcerted the experiment." 



Speaking of the spinach he found the same thing. " In one of my daily visits to my three plants, I perceived upon one individual an 

 unexpected conjunction of male and female flowers, growing close together, and forming very elegant groups. The blossoms with pistils 

 were very conspicuous, but those with stamina were so little advanced, that they could not be distinguished by the naked eye. Both sorts 

 appeared to be equally numerous, but the union extended only to two branches— all the rest bore female blossoms only. I may here inci- 

 dentally remark, that the great abundance of the male flowers, in the present case, is a very singular phaenomenon. I have read in botanical 

 writers, that a few male flowers are sometimes found in company with females, but never that they amount to an equal number, a circum- 

 stance that excited my admiration with respect to this individual; for I counted two hundred and seventy-five male buds." 



But all his experiments on the Dogs Mercury, or French Mercury, turned out according to the now prevaihng opinion. 



The next and last plant producing male and female individuals, on which I made experiment, is the Mercurialis Annua (French 

 Mercury). Five very small plants were removed from a garden, on the 22d of August, into five pots. They were managed in the same 

 manner as the spinach during the winter (xxxii), and were all so far advanced at the beginning of spring, that there was no difliculty in dis- 

 tinguishing the males from the females; of the latter there were three, and these alone were preserved. By the 24th of March blossoms with 

 pistds appeared upon several branches, growing out of the axillcc of the leaves, and in a few days more the number was exceedingly increased. 

 They were borne upon short flower-stalks, and, as usual, consisted of two small seeds or spherical anthers. They were of a green colour 

 and hairy. But here the event was just contrary to what happened in hemp and spinach. The greater part of the blossoms dropped prematurely; 

 of the few that remained the seeds grew for some time, but fell before they were ripe, and when sown, they did not spring. As this took 

 place before the male plants in the gardens and the fields about Pavia were in flower, I began to suppose mercury to be one of those numerous 

 vegetables, which cannot propagate the species without the powder of the stamina. Meanwhile my three plants continued to put forth new 

 branches, and the old ones, instead of withering, vegetated with great vigour; but still the seeds dropped prematurely. This gradual evo- 

 lution and production of fresh branches, was of such long continuance, that they shewed no tendency to decay, but were producing blossoms 

 with pistils when the mercury in the fields was in flower. I therefore began to entertain hopes, that the seeds now put forth, and those 

 which should follow, would succeed better than the earlier seeds, more especially as the pots were exposed to the open air upon a window, 

 and looked into a garden, in which grew several male individuals of this species. But my expectations were disappointed : as long as the 

 three plants continued to thrive, the seeds dropped almost as soon as they appeared; nor did one of those that were sown ever come up. I 

 repeated the experiment two succeeding years with the same event. 



•« It therefore became necessary to vary the mode of conducting it. Being more confirmed in my suspicion, that the sterility arose from 

 want of pollen, which, though it was at no great distance, did not reach my plants, I determined to bring it nearer ; without, however 

 setting mdividuals of the different sexes in the same place. Two male plants of mercury, reared the next year in two pots, were placed on 

 the outside of a window, and two females growing likewise in pots, were set on the outside of another window. Both windows belonged 

 to one room, and had the same aspect. The four roots of mercury were nearly of the same age, and of the same size. And I waited with 

 great anxiety to see whether the females, on account of their vicinity, would be impregnated by the males. The seeds were constantly fall- 

 ing, but not in such abundance as in the former experiment, when the males were at a much greater distance. Those which adhered went on 

 thriving, andseemedasif they would ripen; and they did accordingly arrive at maturity, and, what is of more consequence, were more 

 productive ; for soon after I had sown them in a pot, I had the pleasure of seeing them spring. It therefore appeared probable that the 

 vicmity of the males to the females had been instrumental in occasioning fecundation: their influence could scarce be derived from any source 

 besides the action of the contiguous pollen. ' 



" This experiment obviously required another: it was proper to bring the different individuals nearer to each other; I accordingly placed 

 two males and two females upon the same window. It now became manifest, how much influence the approximation of the two sexes 

 has upon fecundation. The two females retained almost all the seeds which were produced at this time, exceedino- an hundred The seeds 

 grew perfectly ripe, and when put into the ground, were unfolded into as many plants." "^ 



In 



