42 JOURNAL OF SCIENCE. 
may so term it, between these so-called roses, &c. The classifica- 
tion of all these forms having only superficial resemblance to each 
other is a purely artificial classification.’ I have quoted this passage 
as affording very good examplesof the superficial character of popu- 
lar classification in regard to plants; the following will serve the 
same purpose in regard to animais. Professor Nicholson in his 
Manual of Zoology writes :—‘ The excellence of any given classi- 
fication will depend upon the nature of the points which are taken 
as determining the resemblance. Systems of classification, in 
which the groups are founded upon mere external and superficial 
points of similarity, though often useful in the earlier stages of 
science, are always found in the long run to be inaccurate. It is 
needless, in fact, to point out that many living beings, the structure 
ot which is fundamentally different, may nevertheless present such 
an amount of adaptive external resemblance to one another, that 
they would be grouped together in any ‘artificial’ classification. 
Thus, to take a single example, the whale, by its external charac- 
teristics, would certainly begrouped among the fishes, though widely 
removed from them in all the essential points of its structure.’ 
Look now at the classification of the strictly scientific kind :— 
‘Natural’ systems ot classification, on the other hand, endeavour 
to arrange animals into divisions founded upon a due considera- 
tion of all the essential and tundamental points of structure, wholly 
irrespective of external similarity of form and habits. Philoso- 
phical classification depends upon a due appreciation of what con- 
stitutes the true points of difference and likeness among animals; 
and we have already seen that there are morphological type and 
specialisation of function. Philosophical classification, therefore, 
is a formal expression of the facts aud laws of Morphology and 
Physiology.’ The above extract, although specially applicable to 
the classification of animals, may be taken as a fair expression of 
the principles of scientific classification generally. 
‘‘ In the second place there is a great difference between popu- 
lar and scientific classification, in that the former is, at best, only 
partial and incomplete, while the latter is thorough, exhaustive, 
and complete. Under the promptings of a natural tendency, men 
grouped objects into larger or smaller classes in a sort of rough-and- 
ready way, according to superficial resemblance, and it is found 
that a very large proportion of the lower, and a few of the higher 
groups, correspond in value to the species and genera of Biology. 
But such correspondence is rather accidental than intentional. 
No one will imagine that in forming things into groups, there was 
in the minds of ordinary men any clear idea of method and system, 
any distinct notion of a gradation of groups, or of a definite scheme of 
co-ordination and subordination systematically carried out through 
the whole field of inquiry. Things were fairly arranged so far as 
regards the lowest groups or species, but above this all was loose, 
vague, and ill-defined. Scientific classification, on the other hand, 
proceeds on a well-defined plan, and is exhaustive and complete. 
In Biology, for example. individuals are arranged into’ species, 
species into genera, genera into families or orders, orders into 
classes, and these into sub-kingdoms and kingdoms, thus affording 
an exhaustive and systematic scheme of the entire life of our: 
planet. 
“III. In the third place, let me contrast the procedure of 
