68 
PROCEEDINGS OR THE PERTHSHIRE SOCIETY OE NATURAL SCIENCE. 
living species of to-day, but all the vast multitudes of 
extinct creatures which have long since vanished for ever 
from the world. More than this, as observations extend, 
that vague and indistinct line of demarcation which at one 
time was thought to separate the animal and vegetable 
kingdoms, becomes more indistinct than ever, and indeed 
has been shown to have really no existence — the two 
kingdoms merge, as it were, the one into the other. 
But even after we have ascertained all that is known of 
the origin and development of species—of the structure of 
organisms—of their varied modes of life—of their geo¬ 
graphical distribution,—we have not come to the limits of 
our science. There still remains many most interesting 
subjects of inquiry which are intimately connected with 
the life-history of organisms. How has the present geo¬ 
graphical distribution of animals and plants come about ? 
What does it mean ? Here the biologist trenches upon the 
domains of the geologist—another proof of the unity of 
Nature. We soon discover that just as the roots of the 
great genealogical tree of life strike deep into the abysses 
of the past, so are our present lands and oceans only 
reminiscences, as it were, of other lands and waters which 
were the busy scenes of life ages and ages ago. The pre¬ 
sent distribution of animals and plants throughout our 
globe is eloquent not only of former geographical changes, 
but of great climatic vicissitudes. The botanist finds that 
in Northern Scandinavia the low grounds are clothed with 
certain plants which, as he travels southward, gradually 
disappear, and are replaced by other forms, until long be¬ 
fore he reaches Middle Europe the last trace of the peculiar 
flora I refer to has vanished from the low-lying tracts. 
But when he leaves those low grounds and ascends the 
mountains, he again encounters his lost Scandinavian 
friends flourishing vigorously up to the limits of perennial 
snow. How, he asks, did these curious colonies of Scan¬ 
dinavian plants find their way into the mountain recesses 
of the Alps and other high ranges in Middle and Southern 
Europe ? It seems at first a hard riddle to read. But the 
geologist gives a simple solution of the problem. He tells 
the botanist that at one time the climate of Europe was so 
cold that these Scandinavian forms were forced to retreat 
from the high latitudes which they now affect, and to take 
up their quarters upon the low grounds of Germany, where 
their remains occur underneath ancient peat-bogs. But 
when eventually those cold conditions began to pass away, 
then the arctic plants gradually vanished from the low 
grounds of Middle Europe,—migrating northwards into 
Scandinavia, and spreading up contiguous mountain-slopes, 
like the Harz, the Carpathians, the Alps, the Grampians, 
&c., at whose higher levels they still flourish as living 
memorials of the old ice age of Europe. Then, again, the 
botanist and zoologist know that many of the plants and 
animals of Britain are common to similar latitudes on the 
Continent. How is this to be explained ? It is obvious 
that a very large proportion of our species could only have 
entered our area at a time when there was land-connection 
between us and the Continent; and this surmise is abun¬ 
dantly borne out by many collateral facts which have been 
brought to light by geographical investigations. 
You see, then, that the aims and ends of Natural 
History are very far from being restricted to the mere col¬ 
lection of specimens, however necessary and important that 
may be for the purposes of study. Natural History is, in 
short, the history of the origin and development of extinct 
and living plants and animals, and of that solid crust upon 
which those myriad forms have lived and moved and had 
their being. When we once fairly appreciate this philo¬ 
sophical mode of viewing the Natural Sciences, we ought 
to run little danger of becoming mere plodding specialists. 
We shall have our minds elevated and our sympathies en¬ 
larged, with the certain result that our own special work 
will gain alike in interest and importance. By dwelling 
often upon the wider bearings of a Science, we shall 
quicken the imaginative faculty, and thereby sharpen our 
powers of observation, and direct these more readily into 
paths that will give promise of discoveries. 
I have said thus much of the broader aspects of Natural 
Science studies certainly not to discourage anyone in his 
special pursuits. That would be a great misfortune, 
which no one should regret more than myself. It cannot, 
I think, be too strongly Impressed upon young students of 
science that if they ever wish to add a single stone to the 
Temple of Knowledge, they must take up a more or less 
limited field in which to labour with all their might It is 
only the hard and laborious and careful observers who 
attain to any reputation as generalizes. But I have often 
thought that many specialists would have given us more 
and better work if they had not allowed themselves to be¬ 
come cramped and narrowed by continuing too long in one 
rut or groove. They dig so deep that they get into a hole 
out of which they seldom think of climbing just to take a 
look round at what others are doing, and to note how the 
work in general is progressing. This is no imaginary 
danger. At the present time, for example, the interesting 
science of embryology, for a long time comparatively 
neglected, employs a large proportion of working natural, 
ists, whose combined labours have, as I have already 
remarked, revolutionized the study of biology. Everyone 
must admit the magnificence of the results which have 
been attained, and which are still steadily being increased. 
