A certain number of the temporary breakdowns or nervous prostrations, which seem to be growing more common or fashionable, may be sometimes traced to such a deficiency of normal response to the needs of everyday conflict by the adrenal gland. In some, mental and physical elasticity are totally lost, and even the slightest exertion in either field often causes so much weariness and exhaustion as to be prohibited. Depression and even melancholia are associated with the fear of not being able to accomplish good work hitherto easy and enjoyed. Sometimes they are obsessed with the thought that they have lost their nerve completely, and so dread to commit themselves in even the most trivial of situations. The vacillating frame of mind is so distressing at times as to arouse thoughts of suicide. When these symptoms concur in the type of personality whom I shall describe as the unstable adrenal-centered individual, there is evidence for explaining the process as the effect of an insufficiency of secretion by the adrenal gland. Shock, collapse, heart failure and sudden death following abnormal emotion, like an attack of rage, or the terrors of a railroad accident, or bad news, or excessive exertion like running a long race or climbing a high mountain when in poor general health, as the phrase goes, or in the terminal stages of infections like epidemic influenza or Asiatic cholera, have been put down to an acute insufficiency of the adrenal gland. A lowered temperature, blood pressure, and blood vessel tone, exhibited in tests of the response of the skin to stroking, are present in all of these and point the same moral.