444 NOTICES OF THE MEETINGS (May 12, 
WEEKLY EVENING MEETING, 
Friday, May 12. 
Sir Henry Ho.wtanp, Bart., M.D., F.R.S., VinesBersidint 
in the Chair. 
Tuomas Huxtey, Ese. F.R.S. 
On the common Plan of Animal Forms. 
Tue Lecturer commenced by referring to a short essay by Géthe — 
the last which proceeded from his pen—containing a critical 
account of a discussion bearing upon the doctrine of the Unity of 
Organization of Animals, which had then (1830) just taken place in 
the French Academy. Géthe said that, for him, this controversy 
was of more importance than the Revolution of July which immedi- 
ately followed it — a declaration which might almost be regarded as 
a prophecy ; for while the Charte and those who established it have 
vanished as though they had never been, the Doctrine of Unity of 
Organization retains a profound interest and importance for those 
who study the science of life. 
It would be the object of the Lecturer to explain, how the con- 
troversy, in question arose, and to shew what ground of truth was 
common to the combatants. 
The-variety of Forms of Animals is best realized, perhaps, by re- 
flecting, that there are certainly 200,000 species, and that each 
species is, in its zoological dignity, not the equivalent of a family or 
a nation of men, merely, but of the whole Human Race. It would 
be hopeless to attempt to gain a knowledge of these forms, there- 
fore, if it were not possible to discover points of similarity among 
large numbers of them, and to classify them into groups,—one 
member of which might be taken to represent the whole. A rough 
practical classification, based on obvious resemblances, is as old as 
language itself; and the whole purpose of Zoology and Comparative 
Anatomy has consisted chiefly in giving greater exactness to the 
definition and expression of these intuitive perceptions of resem- 
blance. 
The Lecturer proceeded to shew how the celebrated Camper 
illustrated these resemblances of the organs of animals, by drawing 
the arm of a man, and then by merely altering the proportions of its 
constituent parts, converting it into a bird’s wing, a horse’s fore- 
leg, &c. &c. Organs which can in this way be shewn to grade into 
one another, are said to be the same organs, or in anatomical phrase- 
ology are Homologous :— and by thus working out the homologies of 
all the organs of the Vertebrate class, Geoffroy, Oken, and Owen,—. 
to the last of whom, we are indebted for, by far, the most elaborate 
