348 Mr. A. Henfrey on the Progress of Physiological Botany. 
ment of the embryonary globule into an embryo. It must suffice 
to state, that by the multiplication of cells it gradually enlarges 
and acquires a definite form, producing a frond at one end and 
a radicle at the other, bursts through the cavity in which it was 
developed, and grows up, producing new fronds, into the charac- 
teristic form of its species. These ulterior stages of the germi- 
nation from the pro-embryo have been described by other au- 
thors, although not so minutely, and our chief business is with 
the new doctrine of the generation which has already been cri- 
tically examined and contested. 
It must be mentioned here that the terms of Dr. Minter’s 
report * are rather different from the above, which is important, 
as he gives the facts as witnessed also by himself and Prof. Link. 
He says with regard to the act of impregnation :—“ Persevering 
observations of these two essentially different organs gave the 
following results. The spiral filaments emerged from the spon- 
taneously opened hemispherical cells, two or three of them 
moved rapidly toward the cup-lke cellular protuberance, pene- 
trated through the orifice into the still very short blind canal, 
and then were converted into a little heap of mucus (schleim- 
kliimpfechen) after their motion had ceased. After ths (often-ob- 
served) process the quadratic orifice closed, and it was seen that, 
in the blind end, one of the cells lying on the inside of the wall of 
the semi-canal enlarged, and in it new cells origimated.” 
This cell is said to be the embryo, which, elongating in a di- 
rection at right angles to the canal, breaks through in two places, 
one end producing a frond, the other a root. 
In the early numbers of the ‘ Botanische Zeitung’ for the 
present year is contained a long memoir on this subject by Dr. 
Albert Wigand, who, after extensive investigations, arrives at the 
conclusion that the above-described process of impregnation does 
not occur, and that the views of Count Leszezic-Suminski and 
Dr. Minter are based on errors of observation. His criticisms 
would occupy too much space for the present article ; I shall 
therefore reserve them for a future notice, and add to them some 
observations of my own. 
In the ‘Annales des Se. naturelles’ for January 1849, M. 
Thuret describes the antheridia or spiral-filament organs of Ferns, 
but he does not appear to have detected the so-called ovules. He 
also mentions that he has found similar spiral-filament organs on 
the pro-embryo of the Kquiseta. 
* Bot. Zeitung, Jan. 21, 1848. 
