Academy of Sciences in Paris. 361 



sur les Rapports des Sexes dans le Regne Vegetal. 1 The work is 

 divided into two parts ; the first of which contains the details of expe- 

 riments made by the author on hemp, spinach, the Lyc.horis dioica, 

 and wild sorrel, with a view of investigating a variety of phenomena 

 in the generation of plants. M. Giroux has, with incredible patience, 

 made his observations on 20,000 individual plants, 14,000 of which 

 were hemp. In the hemp and spinach, he collected separately the 

 seeds of the top, the middle, and the bottom of the ear, as well as 

 those of the lowest branches and the thinnest stocks; in the Lychoris 

 dioica those of the top and bottom of the trophosperma ; in the sorrel 

 those of the top and bottom of the ear : he then weighed 100 grains of 

 hemp, taken at random from each of the three parts of the last, and 

 found that, assuming the volume of the grains to be in proportion to 

 their weight, those of the bottom part of the ear are the smallest, and 

 those of the middle the largest. He then sowed, separately, each of 

 the qualities of seed, according to the divisions above-mentioned. A 

 short time after the germination, he reduced the number of the hemp 

 to 5000, by suppressing many of the females, which would have in- 

 jured the development of the others, and by the total removal 

 of the males. Notwithstanding the absence of the latter, all the 

 females which were preserved afforded an ample crop of fecund 

 seed ; but it cannot be concluded from this fact, that the fecundation 

 took place without the intervention of male organs, because it is 

 well known, that beneath the envelope of the female flowers of 

 hemp, there are frequently stamina which cannot be removed without 

 mutilating the adjacent organs ; and although these stamina are 

 generally malformed, there is nothing to prove that some among 

 them may not enjoy the property of fecundation. A similar experi- 

 ment, tried on the Lychoris dioica, with a similar result, is more 

 conclusive, if M. Giroux be certain that every precaution of isolation 

 was observed, and that all the flowers were either entirely devoid of 

 stamina, or had their antherse completely removed before the emis- 

 sion of pollen ; but he must assure us of this unequivocally before 

 we can admit the conclusion. The following are the general results 

 obtained by M. Giroux from the above and other experiments: 

 1. The seeds taken from the summit, either of the ear or the tropko- 

 sperm,have constantly produced more females than those taken from 

 the lower part. 2. In hemp, those taken from the lower part pro- 

 duced more females than those taken from the middle. 3. The 

 seeds taken from the thinnest stalks, both from hemp and spinach, 

 produced more males. 4. The hemp seed of medium size produced 

 more females. 5. In hemp, the size of the plants has been in propor- 

 tion to that of the seeds. 6. The numerical relation between the male 

 and female hemp, produced from seeds developed, some in presence of 

 the males and others in their absence, did not ofler any susceptible dif- 

 ference. In the second part, M. Giroux has extended, to a greater 

 length than has ever been done by any preceding naturalist, his obser- 

 vations on the difference between the males and females of a variety 



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