Mania.—­This type of insanity means a raving and furious madness.  There are many cases of this kind.  The causes are many and may be the same as those which produce melancholia.  In melancholia the shock, etc., causes depression, while in the mania the causes of mental injury tend to produce irritation and excitement.  In dementia, the causes of insanity tend to exhaust the body and to mental failure, while in general Paresis “the shock of disease comes after long and unwise contact with worry, wine and women.”  Insufficient sleep often causes mania.  It often follows after exhausting and irritating fevers.  Long continued ill health, together with worry, etc., may cause it.

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To sum up, “mania” may result from any unusual shock or strain upon the nervous system; or it may come after any unusual mental excitement in business, politics or in religion.  Such are the exciting or stimulating causes, but we must go back of the presence of worldly misfortune and trace the tendency to mental disorder through channels of hereditary influence.  “Infants are born every day whose inevitable goal is that of insanity.”  What is said in the Bible about sins of the parents is true.

Dementia.—­This term literally means “from mind,” out of mind, and such a person is in a state of the most deplorable mental poverty.  We all have seen such cases and some cases are not only very sad but disgusting.

Primary dementia comes on independently of any other form of insanity.

Secondary dementia follows after some other form of insanity,—­chiefly melancholia or mania.  Dementia may be acute or chronic.

Senile (old age) dementia may be Primary.—­Acute dementia attacks both sexes, but it occurs most often in females, though in a milder degree.  It is a disease of youth, being rarely seen beyond thirty years of age.  It seems to depend often upon exhausting influences operating at a period of rapid growth.  Monotony of thought and feeling or want of mental food can also induce it.  Children who are sent at an early age into factories often pass into the condition of acute dementia.  Prison life also tends to produce such a condition.  Acute diseases such as typhoid and other fevers are sometimes followed by acute dementia.  Persons frequently go “out of their mind” suddenly in this age, and upon recovering from acute dementia, the patient finds a great “vacancy of memory.”

Chronic Dementia.—­Shakespeare says, “Last scene of all, that ends this strange, eventful history, is second childishness and mere oblivion; sans teeth, sans eyes, sans taste, sans everything.”

“The Sans Everything.”—­Is the sad and hopeless obscuration by time or disease of the once bright, vigorous, scintillating mental powers of exhuperant and lusty youth.  Everyone has seen such people who are partially or hopelessly demented.  It may come from diseases, such as epilepsy and syphilis; alcohol produces it.