666 MEMOIR OF REV. JOHN FLEMING, D.D. 
tion, and the numerous applications which I have made of them in my work on 
fossil bones. You would then probably have allowed that my ideas on the sub- 
ject are less separate from your own after all, and especially you would have 
avoided representing them as in favour of materialism. I do not pray you the 
less, Sir, to receive with many thanks the expression of my most distinguished 
sentiments.” (Signed) “* BARON CUVIER.” 
It required no common courage, especially in a clergyman, to teach a doc- 
trine so opposed to all the opinions of his fellows at this time, that “life and 
death are co-ordinate,” and it is interesting to find a passage in the “ Philosophy 
of Zoology”’ on that gucestio vexata the origin of species (as unsettled now as it 
was then), to which we, in absence of better evidence, may attach our faith. He 
says, “Is the generation of organised beings simultaneous or successive? Have 
they all been created at once, but, in the progress of time, so modified by the 
influence of external agents as now to appear under different forms? Or have 
they been called into being at different periods, according as the state of the 
earth became suitable for their reception? The latter supposition is coun- 
tenanced by many geological documents.” Before we can estimate the value of 
Fleming’s dichotomous method, and its bearings on natural history, we must 
take a short retrospective view of the systems and methods of his predecessors. 
Two great divisions of the animal kingdom have been generally acknowledged — 
and justly appreciated since the days of Aristotle,—animals possessing warm and 
red blood, and those without blood—proper.* Those positive and negative distinc- 
tions, under various forms and modifications, still constitute the foundation of 
all our scientific systems and classifications. This primary division was adopted 
by Aristotle, and is essentially founded upon physiological principles. Man was 
selected as the standard of comparison, and the viviparous animals, birds, rep- 
tiles, and fishes, follow in succession. From the time of this great master of 
science until the beginning of the sixteenth century, no advance was made in 
these “dark ages,” of which Owen remarks, “The well-lit torch, which should 
have guided to further explorations of the mighty maze of animated nature, was 
suffered to fall from the master’s hands, and left to grow dim and smoulder 
through many generations, ere it was resumed, fanned anew into brightness, and 
a clear view regained both of the extent of ancient discovery and of the right 
course to be pursued by modern research.” 
The elder Pliny made no attempt at a scientific method of arrangement 
further than commencing with the largest group and ending with the smallest. 
During the sixteenth century, with the revival of learning, a better era dawned 
upon the study of natural history. This originated with BELon of Mans, who was 
born in 1517, and seems to have devoted himself to the study of birds, fishes, 
and botany. 
* See Aristotle’s System, Linnean Transactions, vol. xvi. p. 24. 


