the most peremptory causes of the discharge of energy is that due
to an attempt to obstruct forcibly the mouth and the nose so that
asphyxia is threatened. Under such conditions neither friend
nor foe is trusted, and a desperate struggle for air ensues.
It will be readily granted that the reactions to prevent suffocation
were established for the purpose of self-preservation, but the discharge
of nerve-muscular energy to this particular end is no more specific
and no more shows adaptive qualities than do the preceding examples.
Even the proposal to bind one down hand and foot excites resentment,
a feeling originally suggested by the need for self-preservation.
No patient views with equanimity the application of shackles
as a preparation for anesthesia.

We have now considered some of the causes of those discharges of nervous
energy which result from various types of harmful physical contact,
and have referred to the analogous, though antithetical,
response to the stimulation of the sexual receptors.
The response to the adequate stimuli of each of the several receptors
is a discharge of nerve-muscular energy of a specific type; that is,
there is one type of response for the ear, one for the larynx,
one for the pharynx, another for the nose, another for the eye,
another for the deep ticklish points of the chest and the abdomen,
quite another for the delicate tickling of the skin, and still
another type of response to sexual stimuli.

According to Sherrington, a given receptor has a low threshold
for only one, its own specific stimulus, and a high threshold
for all others; that is, the doors that guard the nerve-paths
to the brain are opened only when the proper password is received.
According to Sherrington's law, the individual as a whole responds