223 
de cette fameuse theorie de revolution/* which, he tells us, 
had produced more than three hundred hypotheses. He then 
passes on to more modern discoveries and hypotheses, and to 
the memorable researches of Pander and De Baer, the latter of 
whom, in describing for the first time the egg of the mammifers, 
in proving the existence of the ovarian cellule amongst all 
animals, impressed an entirely new aspect on embryology. 
And yet De Baer (if the same with Y on Baer, as I suppose) 
was, as we see, no Evolutionist. 
Agassiz (who also refused the fashionable doctrine) asserted 
that the discoveries of De Baer were the most beautiful that 
have been made in the natural sciences in modern times. 
But the German “ hyperDarwinist,** Haeckel, comes forward 
with a new theory, according to which “ the theory of types of 
Cuvier and of De Baer, which, during half a century and to our 
days, has formed the base of the zoological system, has become 
untenable * through the progress of ontogenie, and must yield 
to that phylogenetic classification of the animal kingdom of 
which the theory of the Gastrcea forms the essential basis.** 
This promising young theory was to have demonstrated that 
all the different branches of the animal kingdom descend from 
only one unknown ancestral form, which developed itself bg 
spontaneous generation , of which the organization was essen- 
tially the same as that of the gastrula. It is this form, long 
since extinct, which lived during the Laurentian period, and 
which M. Haeckel described under the name of Gastrcea. 
The very complete analysis of this theory by Moquin- 
Tandon leads to certain conclusions, of which it is sufficient 
for me to quote as epitaph : — 
“ The hypothesis of the Gastrcea as the ancestral form 
common to all animals with the exception of the Protozoa, 
rests on no fundamental fact, and cannot serve as a basis 
for a phylogenetic classification.** This theory was con- 
cocted in Germany ; it is defunct in France, and entombed 
in the “Annales** from which I quote, but will probably 
be galvanized into life in England, as the place of its birth 
will give it to some minds an imperishable charm. It 
constitutes the basis of a not inconsiderable section of Dr. 
Tkomson*s Address, and though he has the modesty to 
acknowledge that the Gastrcea theory is not quite proven, he 
leaves us under the impression that it is a most promising 
tentative experiment, so that “ we are at least in the track 
* l. c., p. 14 , 
Q 2 
