320 The Naturalist in La Plata. 
enced by the animal ata period when its curious 
instinct first took form and crystallized; these 
would be painful sensations that threatened life ; 
and freedom from them, and safety to the animal, 
would only exist in a certain well-remembered spot. 
Further, we might assume that it was at first only 
the memory of a few individuals that caused the 
animals to seek the place of safety; that a habit 
was thus formed; that in time this traditional habit 
became instinctive, so that the animals, old and 
young, made their way unerringly to the place of 
refuge whenever the old danger returned. And 
such an instinct, slowly matured and made perfect 
to enable this animal to escape extinction during 
periods of great danger to mammalian life, lasting 
hundreds or even thousands of years, and destruc- 
tive of numberless other species less hardy and 
adaptive than the generalized huanaco, might well 
continue to exist, to be occasionally called into life 
by a false stimulus, for many centuries after it had 
ceased to be of any advantage. 
Once we accept this explanation as probable— 
namely, that the huanaco, in withdrawing from the 
herd to drop down and die in the ancient dying 
ground, is in reality only seeking an_ historically 
remembered place of refuge, and not of death—the 
action of the animal loses much of its mysterious 
character ; we come on to firm ground, and find 
that we are no longer considering an instinct abso- 
lutely unique, with no action or instinct in any 
other animal leading up or suggesting any family 
likeness to it, as I said before. We find, in fact, 
that there is at least one very important and very 
