1864. | Comparative Anatomy and Classification. 535 
classification, is that it has a value apart from the knowledge of the 
objects of which it treats. As this is a somewhat vague expression, 
we would explain it by saying, that the knowledge how to classify is 
one science, whilst an intimate acquaintance with the subjects classified 
is another ; it is not at all unusual to find a clever systematiser who 
has little intimate practical knowledge of the large majority of objects 
which he arranges according to their leading properties, whilst there 
are innumerable so-called practical men of science to whom systems of 
classification are almost unknown. When, however, we meet with 
an individual proficient in both departments of knowledge, it may 
naturally be expected that any new arrangements proposed by such 
an one, will be valuable to students and observers. In no branch 
of science have there been greater changes in regard to classifica- 
tion than in natural history; and when we restrict that term to its 
popular signification, zoology, we cannot fail to be struck with the 
great number of systems which have from time to time been recom- 
mended by men of undoubted eminence, subjected to alterations, 
corrections, and emendations, and which have superseded one another 
with astonishing rapidity. To the young beginner this circumstance 
is often a matter of great perplexity, and he frequently finds that when 
at the recommendation of a friend or teacher, having a particular bias, 
he has mastered the arrangement of some well-known systematic 
zoologist, he has a great deal to unlearn, before he can renew his 
studies on a par with those who have availed themselves of more 
recent, or perhaps more accurate systems of classification. 
Some years ago, a favourite book with beginners was Rymer 
Jones’s ‘ Natural History of Animals,’ * a very attractive little work, 
well written, and beautifully illustrated, and one that has no doubt 
raised up many an active and useful devotee of science. The author 
of this book, believing all methods of classification propounded up to 
his time to have been very imperfect, set to work to build up a new one 
based upon the most recent experiences of his day. Aristotle, he told 
his readers, had simply classed all animals under two great heads,the one 
possessing colourless, and the other red blood, divisions which corre- 
spond with the invertebrata and vertebrata. Passing from the old Greek 
philosopher to the fathers of modern zoological science, he touched 
upon the systems of Linnzus and Cuvier, both of whom, recognizing in 
the structural peculiarities of animals suitable guides for classification 
(the external horny cases in insects, or the internal bony framework 
of the vertebrata, for example), based their arrangements upon these 
characteristics. But because the author could not find in them squares 
ready fitted to receive some of the more recently discovered forms of 
life, he was dissatisfied with both these systems, and regretting that 
the celebrated John Hunter had not lived long enough to carry out his 
physiological views in regard to classification (inasmuch as that great 
anatomist had obtained “an indistinct glimpse of the clue that would 
have served to guide him”’), he announced that the researches of 
modern physiologists had “ fortunately left us in no doubt upon the 
* Van Voorst, 18+5. 
