74 PROF. J. ARTHUR THOMSON ON 
All this, enigmatical as it may seem at first sight, and 
commonplace at second sight, is by way of introduction to 
my proper subject here, which is the biological importance 
of play. For play—whether of animals or of men—would 
surely have been regarded by the staid naturalists of a pre- 
Darwinian school as a sort of aside in nature, to consider 
which would compromise their dignity as scientific workers, 
the fact being that its careful study, as Professor Groos has 
shown, raises the deepest problems. 
And here I may at once admit frankly that, in regard to 
my subject, I have nothing original to communicate, apart 
from a slight personal equation. I have, indeed, often 
watched and thought about the play of animals—the kittens 
and their ball, the dogs and their sham-hunt, the lambs and 
their races, the monkeys and their “ tig’”—but I never got 
to clearness until I read Professor Groos’s Spiele der Thiere 
(Jena, 1896); translated as The Play of Animals (London, 
1898); and recently followed by another volume on human 
play, Die Spiele der Menschen (Jena, 1899). The author 
has brought his knowledge of biology, esthetics, and 
psychology to bear upon the subject of play with a success 
which makes his work one of the most important recent 
contributions to comparative psychology. 
I have not attained to any definition of play—that comes 
last, not first—nor does it matter much, since, I suppose, we 
all have vivid reminiscences or present experience of what 
play means. To say the least, it is very widespread among 
mankind, though one reads in Mr Kearton’s entertaining 
book, With Nature and a Camera, the following sentences in 
regard to the people of St Kilda :—‘“TI innocently asked the 
minister one day what kinds of games the children played. 
The old man smiled good-naturedly at my ignorance, and 
answered: ‘None whatever; their parents would consider 
it frivolity to have them taught anything except climbing 
rocks, catching sheep, and such other things as will become 
necessary to them in after-life.’” Now, though I do not go 
the length of placing play quite in the foreground of life, as 
a brilliant artistic friend did when he spoke of life as a series 
of interruptions from golf, I do think that the good folk of 
St Kilda would increase their present and future effective- 
