260 MR. NEWPORT ON THE IMPREGNATION OF THE OV’^UM IN THE AMPHIBIA 
subject of his particular investigation^; and M. BRONGNiARTf, ScHLEiDExt, NIgeli^, 
Griffith 11, and more recently Suminski^ and Henfrey^^ liave 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. HoFMEisTERff , and very recently also Mr. Henfrey:J:^, 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, 
Siebold, Muller, Wagner, Kolliker, Bischoff, 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 decidelllj. Heretofore I regarded impregnation as being commewce^ 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 bemg 
only the visible indication of a 'peculiar force, ov 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 iii 
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 wit i 
the vitelline membrane,!^ 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, 1S2/, on 
the particles contained in the pollen of plants, and on the general existence of active molecules in organic and 
inorganic bodies, by Robert Brown, F.R.S., etc., Svo. July, 1828 ; also additional remarks on active molecules. 
{Id.) July, 1829. ^ /x- ^ \ 
t Recherches sur la generation et le developpement de I’embryon dans les Vegetaux Phanerogames (Notes;. 
Annales des Sciences Nat. tom. ix. 1828. 
X Grundziige der wissenschaftliche Botanik. 
§ ScHLEiDEN und Nageli’s Zeitschr. fiir Wiss. -Botanik ; Heft i. 168; Zurich, 1844. 
II Transactions of the Linnean Society of London, vol. xx. 
^ Zur Entwickelungsgeschichte der Farrnkriiuter, 4to. Berlin, 1848. 
** On the development of the ovule in Orchis niorio. Transactions of the Linnean Society of London, 
vol. xxi., and Proceedings, vol. ii. p. 27, April 8, 1849. ^ ^ ^ 
f-j- Untersuchung des Vorganges bei der Befruchtung der CEnothereen, Botanische Zeitung, v. /85, 184/. 
1+ Annals and Magazine of Natural History, vol. ix. June, 1852 ; Transactions of Linnean Society, vol. xxi 
Part 11. ; also Proceedings, June 17, 1852, vol. ii. 
§§ Annales des Sciences Naturelles, tom. ii. 1824. 
1111 Article “ Semen,” Cyclopaedia of Anatomy and Physiology, vol. iv. par. xxxiv. p. 508. 
