78 PROF. J. ARTHUR THOMSON ON 
again to the brain, and when the circle is completed, so to 
speak, we are pleased. We cannot but think that we are 
thus brought nearer an understanding of the origin of the 
vocal play—the song—of birds, which is due to internal 
muscular movements associated with strong emotions, © The 
fact, at least, is that there is a subtle connection between 
emotion and motion. Literally, Wordsworth’s heart leaped 
up when he beheld the rainbow in the sky, and filled with 
pleasure as he beheld the dancing daffodils. 
Perhaps we should remember this in relation to the 
noisy racketings of children, which are often so un- 
pleasant on purely esthetic grounds. They are probably 
often quite natural expressions of emotions, for which it is, 
of course, our business to offer more appropriate channels of 
expression. 
The play-nature of many movements is particularly plain 
when there is anything unusual about them. Thus Alix 
relates that, on one occasion when botanising on the Alps, 
his dog ceased to follow him on the gradual path, and 
seemed deliberately to choose a long slope of frozen snow. 
There he lay down on his back, folded his legs, and slid 
down like a toboggan. At the foot he rose quietly, looked 
up to his astonished master, and wagged his tail. Alix 
imagined that his dog had thought out the short-cut; it 
seems to me much more likely that it was simply play— 
done for fun! 
Of course, we are agreed that all movements which can 
be shown to be of direct material advantage must be placed 
outside the category of play; but, however strict one is, 
many indubitable cases remain. 
When Romanes says of fishes, “nothing can well be more 
expressive of sportive glee than many of their movements,” 
you may not be convinced. When Hudson says, “I have 
spoken of the fire-fly’s pastimes advisedly, for I have really 
never been able to detect it doing anything in the evening 
beyond flitting aimlessly about, like house-flies in a room, 
hovering and revolving in company by the hour, apparently 
for amusement,” you may still be unconvinced; but I 
think you will at once admit the genuineness of move- 
ment-play if you watch macropod fishes in their tank, or 
