AS A SOURCE OF ACTION IN ANIMALS. 
577 
Of these latter sources, or principles of action, instinct only, as we 
shall find, is entirely independent of any exercise of memory in 
reference to prior sensations or impressions. Therefore, when in 
addition to the direct and unequivocal influence of memory, whose 
extensive diffusion through the animal kingdom we shall, it is 
hoped, be able satisfactorily to establish, we take into account its 
indirect influence, as manifested through processes of intellectual 
action, or a species of reasoning and mental feeling or emotion, the 
vast importance of this faculty, as a stimulant and guide of action 
in many different genera and tribes of animals, at once discloses 
itself, challenging very forcibly detailed inquiry and exposition. 
It is certainly only consistent with ordinary correctness to refer 
phenomena to their proper causes, and this equally in the 
psychical and in the physical world. But certain it is that almost 
all recent writers on instinct, of any degree of celebrity, have 
referred many phenomena to this peculiar influence, which more or 
less evidently pertain to an operation of memory, or the intel- 
lectuality of the animals. This, undoubtedly, is an error which 
imperatively calls for correction, at least as far as may be. Hence, 
in order to place the subject in a proper light, to distinguish those 
actions which are the result of memory from those that belong to 
instinct, — in a word, to eliminate, as far as practicable, truth from 
error, — it will be absolutely necessary to go somewhat largely into 
details ; — to review not only the phenomena of memory in animals, 
and those active mental manifestations connected with their nature, 
involving, as an essential condition, an exercise of this faculty, 
but also the principle of instinct itself, and its immediate con- 
sequences or effects. With a view to this important object the 
following communications are placed at the option of The Lancet ; 
and, although the ground which we shall have to traverse is, as 
will be apparent, rather extensive, and rich besides in topics of 
no ordinary interest, still I hope not to trespass too largely on the 
valuable space of that journal. 
Memory, as is perfectly clear, pertains not exclusively to the 
mental or intellectual constitution of man : it exhibits itself, also, 
in some degree, in many, very many, of the lower animals, in- 
fluencing, or guiding and controlling their actions to an extent 
little short, probably, of that of the power of instinct itself. 
With reference to all the higher species of animals, the indica- 
tions of the influence of memory are numerous indeed, and most 
unequivocal; and it may be stated here, generally, that in them, 
equally as in ourselves, it constitutes the main-spring of all those 
actions that have conventionally been denominated intelligential. 
But, in regard to the more humble and essentially instinctive orders 
and tribes of creature life, the existence and active play of this 
VOL. XVII. 4 G 
