260 MR. NEWPORT ON THE IMPREGNATION OF THE OVUM IN THE AMPHIBIA 



subject of his particular investigation *; and M. BRONGNIART-|-, SCHLEIDEN;}:, NAGELI^, 

 GRIFFITH ||, and more recently SUMINSKI^[ and HENFREY** have done the same. 

 But although neither of these able inquirers succeeded by direct experiment in 

 proving that the motion of the particles of plants is essential to the act of impregna- 

 tion, M. HoFMEisTER-{~f-, and very recently also Mr. HENFREY^, have noticed facts 

 in regard to that of the spermatozoid filaments discovered by NAGELI and SUMINSKI, 

 in the Cryptogamia, which seem to show that, in plants, it is of great importance to 

 the function of these bodies. The motion of the spermatozoon in animals has equally 

 attracted the attention of zoologists. PREVOST and DUMAS, as already stated, 



SlEBOLD, MuLLER, WAGNER, KoLLIKER, BlSCHOFF, QuATREFAGES, and especially 



WAGNER and LEUCKARDT, have studied it attentively ; but so intricate is the inquiry 

 concerning its nature and import, that the last two authors dismiss the consideration 

 of the question without arriving at any conclusion, and state that they do not venture 

 to decide || ||. Heretofore I regarded impregnation as being commenced by transmission 

 from the spermatozoon on the surface of the egg, to the contents in the interior, of 

 some influence characterized by motion. But I have regarded this motion as being 

 only the visible indication of a. peculiar force, or form of vitality, in the impregnating 

 agent, the spermatozoon, by which it is destined to arrive at, and is to expend on the 

 object to be fecundated, and the effect of which is to strengthen, to augment, and 

 possibly also to modify the nature of the formative changes, which are going on in 

 the yet unimpregnated egg, per se ; but which will subside, and soon entirely cease, 

 if not reinforced through the agency of the spermatozoon. Nevertheless, I have not 

 been prepared to assent to the view that simple contact of the spermatozoon, even with 

 the vitelline membrane, is sufficient to complete the changes which result in the forma- 

 tion of the embryo (see p. 233). The powerful endosmic action of the envelopes of the 

 ovum, at the time of oviposition, is opposed to this conclusion ; since, if simple contact 



* A brief account of microscopical observations, made in the months of June, July and August, 1827, on 

 the particles contained in the pollen of plants, and on the general existence of active molecules in organic and 

 inorganic bodies, by ROBERT BKOWN, F.R.S., etc., 8vo. July, 1828 ; also additional remarks on active molecules. 

 (Id.) July, 1829. 



t Recherches sur la generation et le developpement de 1'embryon dans les Vegetaux Phanerogames (Notes). 

 Annales des Sciences Nat. torn. ix. 1828. 



J Grundziige der wissenschaftliche Botanik. 



SCHLEIDEN und NAGELI'S Zeitschr. fur Wiss.-Botanik ; Heft i. 168; Zurich, 1844. 



|| Transactions of the Linnean Society of London, vol. xx. 



5f Zur Entwickelungsgeschichte der Farrnkriiuter, 4to. Berlin, 1848. 



** On the development of the ovule in Orchis mono, Transactions of the Linnean Society of London, 

 vol. xxi., and Proceedings, vol. ii. p. 27, April 8, 1849. 



ft Untersuchung des Vorganges bei der Befruchtung der OZnothereen, Botanische Zeitung, v. 785, 1847. 



\\ Annals and Magazine of Natural History, vol. ix. June, 1852 ; Transactions of Linnean Society, vol. xxi. 

 Part II. ; also Proceedings, June 17, 1852, vol. ii. 



Annales des Sciences Naturelles, torn. ii. 1824. 



Illl Article " Semen," Cyclopaedia of Anatomy and Physiology, vol. iv. par. xxxiv. p. 508. 



