SONGS OF BIRDS. _ 359 
contrary to the one he tries to advocate, he makes 
them of no value whatever. Mr. Rennie on the 
other hand does not appear to have been aware of 
them, but altogether concludes that weather has 
no effect except in so far as it influences the sup- 
plies of food, whereas I am of opinion that weather 
is of equal importance with food in stimulating the 
animal spirits,—Mr. Rennie makes it subservient 
to food, J wish to elevate it to the same rank in 
exciting the animal spirits, for allowing all neces- 
sary weight to the influence of food on song, it 
would follow that if weather had no separate in- 
fluence, and food a direct influence, song suspended 
when snow and frost concealed supplies of food, 
would be resumed during ordinary weather when 
food was easily obtainable, whereas by the follow- 
ing facts we shall see it is resumed only on the 
occasional occurrence of unusually fine weather in 
the brumal season, so far as regards those species 
in which they were observed. 
I take it, that if song is capable of being excited 
through stimuli on the animal spirits, the circum- 
stances attending on particularly fine weather are 
as likely to act as excitants, as the circumstance 
of the occurrence of food; and by analogy we see 
that intervals of fine warm weather in the more 
uncomfortable months act favourably on the vigour 
of our own frames, and on the domestic creatures 
about us. 
By the geographical position of South Devon as 
respects the poles and the equator, and by the 
ordinations of nature for equalizing the general 
temperature of the earth, besides a number of other 
benefits obtained by cold, it has been directed that 
we should experience severity of weather in the 
course of the winter months, but owing to the 
operation of some secondary influences on climate, 
these cold periods consist only of temporary ces- 
