PROF. J. ARTHUR THOMSON ON THE PLAY OF ANIMALS. 73 
A paper was read by Mr Rosert TurNBULL, B.Sc., on 5th 
January 1899.* 
A paper was read by Mr Joun S. Frert, M.B., C.M.,, 
B.Se., on 19th January 1899. 
THE PLAY: OF ANIMALS. 
(Being for the most part a review of the recent work of GRoos.) 
By Prof. J. ArrHuR Tuomson, M.A, F.R.S.E. 
(Notes of a paper given before the Society on 2nd F ebruary 1899.) 
ONE of the most important indirect results of Darwinism 
has been to convince naturalists that no fact of life is trivial. 
To the inquisitive spirit everything is a problem, but the 
problem is illumined when we realise, as Bagehot put it, 
that everything is “an antiquity,” the product of a past often 
inconceivably long—an event, a personage, or, it may be, 
only a “ property ” in the drama of evolution which has filled 
the world-stage for millions of years. Moreover, it was 
part of Darwin’s genius that he realised, more than any 
other, the solidarity of nature and the inter-relations of 
things. The Systema Nature was the crowning work of 
Linneus; but it was a new system of nature which Darwin 
disclosed—a web of life—in which even the apparently 
trivial fact is invested with momentous importance because 
of its complex correlations with others. A moth, escaping 
from an entomologist’s window, costs the United States a 
million of dollars; a few sparrows and rabbits, transported 
from their native home, disturb the balance of life in two 
continents. The clay-clod on a bird’s foot may affect the 
fauna and flora of a district; and everyone knows how cats 
are linked to clover-crop, and ivory-backed brushes to the 
slave-trade. 
* This paper will appear in next volume of Transactions. 
VOL. I. 6 
