174 The Naturalst in La Plata. 
interesting subject; and although it is not pro- 
bable that anything very fresh remains to be said 
about it, 1 am tempted to add here the results of 
my own experience. 
When travelling by night, I have frequently 
been struck with the behaviour of my horse at the 
sight of natural fire, or appearance of fire, always 
so different from that caused by the sight of fire 
artificially created. The steady gleam from the 
open window or door of a distant house, or even 
the unsteady wind-tossed flame of some lonely 
camp-fire, has only served to rouse a fresh spirit in 
him and the desire to reach it; whereas those m- 
frequent displays of fire which nature exhibits, such 
as lightning, or the ignis fatuus, or even a cloud of 
fireflies, has always produced a disquieting effect. 
Experience has evidently taught the domestic horse 
to distinguish a light kindled by man from all 
others; and, knowing its character, he is just as 
well able as his rider to go towards it without ex- 
periencing that confusion of mind caused by a glare 
in the darkness, the origin and nature of which is 
a mystery. The artificially-lighted fire is to the 
horse only the possible goal of the journey, and is 
associated with the thought of rest and food. Wild 
animals, as a rule, at any rate in thinly-settled 
districts, do not know the meaning of any fire; it 
only excites curiosity and fear in them; and they 
are most disturbed at the sight of fires made by 
man, which are brighter and steadier than most 
natural fires. We can understand this sensation 
in animals, since we ourselves experience a similar 
one (although in a less degree and not associated 
