THE VEGETABLE CELL. 1S7 



the Oryptogamia ; yet there exists an important distinction fi-om 

 t!ie formation of buds, in the fact that the lower end, connected 

 with the suspensor, becomes detached from this, and is capable of 

 further development, in consequence of which the primary axis of 

 the embryo can become elongated downwards, in germination, as 

 a tap-root, which is not the case in any buds, or in the young 

 stems of the Oryptogamia,* the axis of which is only capable of 



prolongation upwards 



» 



Ohserv. L Schleiden's theory of the origin of the embryo ('' Minige 

 Blicke aufdie EntwickelungsgescM elite des veget. Organismus^^ Wiegmann's 

 ^^AtcIivo'' 1837, 1, 289 — " Ueber die Bildmig des Bichens und BntsteJiung 

 des Bmhryo'' Act. acad. nat Otir. v. xix., p. 1.) is completely opposed to 

 the foregoing description of this procebS, since, according to him, the 

 embryo is not formed in the cavity of the embryo-sac, but in the lower 

 end of the pollen-tube, which mtroverts the wall of the embryo-sac, and 

 penetrates more or less deeply into the depi-ession thus formed. If this 

 theory were true, the germinal vesicle would not he an hidependent pro- 

 duct of the ovule, but of the clavate, expanded extremity of the polien-tube, 

 and the suspen&or would be the remainder of the latter, ranning into the 

 mtroverted portion of the embryo-sac. In the whole province of Vege- 

 table Physiology, seldom has a theory excited so much curiosity as this 

 theory of impregnation. ISTo conviction was moi*e firmly established than 

 that the pollen was the impregnating organ, hence the wonder that it 

 should be exactly the reverse. The confusion was great, for the theory 

 emanated from a man who shewed by his numerous and excellent re- 

 searches on the ovule, pubHshed at the same time, that he possessed an 

 acquaintance with his subject, such as few others had, and who in every 

 word expressed the conviction that the matter did occur as he asserted, 

 and that a mistake was out of the question. And others were not want- 

 ing to make known confirmatory observations (Wydler, *' BihliotK Uni- 

 mrs" 1838, Oct.; Geleznoff, " Bot. Zeitung,'' 1843, 841), or to support 

 the new doctrine on theoretical grounds, and teach it as a settled truth 

 (Endhcher and linger, " Grundz der BotanW). It is true that the old 

 notion had its defenders, but these maintamed the fight a long time with 

 little success. Some who did not know how to use the microscope, thought, 

 nevertheless, that an opinion might be arrived at here, in which the thing 

 depended wholly and solely upon a fact to be determined by the micro- 

 scope, from other grounds, but such was utterly without value by itself ; 

 others, Meyen in particular (^^ Physiologie^' in), certainly had recourse to 

 the microscope, but were content with superficial observations, and thus 

 were not very fortunate in their intended refutation of the new theory, 

 for observations, in some of which not even the penetration of the pollen- 

 tube into the ovule, or the embryo-sac were seen, were not calculated to 

 drive an opponent like Schleiden out of the field, and the latter could 

 justly interpret some among such discordant observations as Meyen's in 

 his own favour. It was Amici again who now for the second time came 

 forward with an observation marking an epoch in the theory of impregna- 



'* An error ; the axis of the Ferns, &c., originates from a free embryonal 

 vesicle, and has an abortive descending axis, like the Monocotyledona — 



-A.. jjL. 



