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THE PKINCIPLES OF BIOLOGY. 
and lierbs, and flower and seedless plants. So in the world 
of animals, the beasts, birds, fishes, and creeping things of 
the Mosaic philosophy, groups which differ from one another 
in conspicuous features of appearance and mode of life, these 
are the first formed divisions, and to this day the vast 
proportion of humanity to whom it is known would regard 
the whale as a fish because its habit of life appears to 
resemble that of fishes. 
Coming to distinct attempts at classification, we find the 
“one attribute” principle, or, at the most, simple departures 
therefrom, first in use. This is peculiarly the case with the 
vegetable kingdom. The corolla, the fruit, the calyx and 
corolla, and the stamens and pistil have provided by their 
modifications the principles for classification. The last of 
these, in the well-known Linnsean system, is still in wide 
popular use. But of these early attempts at classification 
many of the secondary groupings are much more philosophical, 
as for example is that of Ray. In classification, the old battle 
of the Aristotelian versus the Baconian philosophy has had 
to be fought out. The earlier systems were all Aristotelian 
in principle ; some are more or less so still, while the 
ultimate classification must be on Baconian lines ; the units 
must be studied before the groups, the groups before the 
classes. Accurate classification works upwards. For long the 
ultimate form of vegetable classification given by Spencer 
has been superseded, and for the last score of years or more 
English botanists at any rate have abandoned attempts to 
make systems, and have devoted their attention to the 
practical application of the law italicised above, by the study 
of the units of the vegetable kingdom, and attempting then 
to define the limits of genera. 
In all modern systems of classification, the linear arrange¬ 
ment has disappeared, and instead of it appear groups and 
sub-groups whose relations with one another are very various, 
and dependent on internal as well as external organisation, 
on organs as well as on members. And the marked tendency 
of modern classifications is to base the widest groupings on 
points of physiological, the narrower of morphological 
importance. Internal organisation is of higher classificatory 
importance than external form. The newest tendency 
throws things still further back. Believing that the early 
history of an individual shadows the past history of its 
race, the modern systematist becomes more and more embryo- 
logical, and here the Baconian philosophy must of needs have 
fullest play. One thing is clear. Linear arrangements are 
tilings of the past. 
