certain muscles or glands into action; and all this may take place
without any sensation or consciousness on our part, though often
thus accompanied. As many reflex actions are highly expressive,
the subject must here be noticed at some little length.
We shall also see that some of them graduate into, and can hardly
be distinguished from actions which have arisen through habit?
Coughing and sneezing are familiar instances of reflex actions.
With infants the first act of respiration is often a sneeze,
although this requires the co-ordinated movement of numerous muscles.
Respiration is partly voluntary, but mainly reflex, and is performed
in the most natural and best manner without the interference of the will.
A vast number of complex movements are reflex. As good an instance
as can be given is the often-quoted one of a decapitated frog,
which cannot of course feel, and cannot consciously perform, any movement.
Yet if a drop of acid be placed on the lower surface of the thigh
of a frog in this state, it will rub off the drop with the upper
surface of the foot of the same leg. If this foot be cut off,
it cannot thus act. "After some fruitless efforts, therefore, it gives
up trying in that way, seems restless, as though, says Pfluger,
it was seeking some other way, and at last it makes use of
the foot of the other leg and succeeds in rubbing off the acid.
Notably we have here not merely contractions of muscles, but combined
and harmonized contractions in due sequence for a special purpose.
These are actions that have all the appearance of being guided
by intelligence and instigated by will in an animal, the recognized
organ of whose intelligence and will has been removed."[10]


[9] Prof. Huxley remarks (`Elementary Physiology,'
5th edit. p. 305) that reflex actions proper to the spinal cord