Classification of Animals. 553 
induced to devote more space to the developement of the leading 
principles of this system, than we should otherwise have done, on 
many important accounts. First, Because it is unquestionably the 
first which clearly defined any one philosophic principle of classifi- 
cation, so that, strictly speaking, we must date the first partial de- 
velopement of natural arrangement from the publication of the 
Horse Entomologicse. Lamarck, it is true, traced the outlines of 
the circle without knowing that he had done so ; while Mr M'Leay, 
by a totally different process of investigation, arrived at the same 
general result, but with this difference ; that he discovered pro- 
perties which belonged to this series of universal prevalence in na- 
tural groups, and he determined several of those laws which regu- 
lated the variation of animals ; a process of induction which hereto? 
fore had never been dreamed of. These discoveries let in a flood of 
light on the study of nature, and converted that which had been a 
science of observation into one of the deepest philosophy." The 
Sy sterna Mycologicum of M. Fries is afterwards noticed, which is bas- 
ed upon the three great principles of natural classification announced 
a little previously by Mr M'Leay, but of which fact this eminent 
botanist was altogether ignorant when he made the same Discoveries 
during his investigation of a group of the vegetable kingdom. The 
only point of difference between them is in the determinate number 
of their groups, those of M'Leay being five, while those of M. 
Fries are apparently four, we say only apparently, for they are in 
reality five, as he confesses that his centrum or typical group is al- 
ways divisible into two series. Modifications which Mr M'Leay 
made in his system are afterwards noticed, as well as the views 
of other writers in regard to natural arrangement ; and the chap- 
ter concludes with some general remarks which may, we hope, 
prevent in future any of those deviations from the true principles 
upon which the circular theory is established, and which can only 
tend to bring it into disrepute. Having taken a review of the va- 
rious systems, artificial as well as natural, which have appeared, he 
proceeds, in the third part of the volume, to lay before his readers 
the result of his own researches on the first principles of the natu- 
ral system, which are embodied in the following five propositions :* * 
1. That every natural series of beings, in its progress from a 
given point, either actually returns, or evinces a tendency to return 
again to that point, thereby forming a circle. 
2. The primary circular divisions of every group are three ac- 
tually, or five apparently. 
