In the foregoing it has been my endeavor to explain, as well as I can, physical reflexes, their causes and variations; also to give a hint regarding the diseases brought on from overwork and underwork.

Nervous reactions, when expressed in the highest order, are mental or physical. All ideas, as well as all movements, have an external origin.

The spiritualistic school will not agree that our psychical nature is built from sense-impression, and that, for us to learn or know anything, we must have sensation. Our special senses are educated by external impressions. Without external stimulation, or without the sense-perception to recognize external impressions, we remain in ignorance--a state of ignorance known as idiocy.

Mind-potentiality evolves as the ages roll on. We do not inherit mind or innate ideas; we do inherit potentiality--an aptitude to understand. Probably the most potent factor in this inheritance is power of attention. With mental alertness a child will gather knowledge so rapidly that to dull pupils it will appear as though it must have inherited its knowledge.

The study habit, when once formed, is a great help to the dull mind.

Mind can never come into its own until man ceases to build physical disease. The mind of a sick man is handicapped. Habits that build disease of the body affect the mind also.

It is common knowledge that the character and type of intelligence and capacity for work are under the influence of various diseases. For instance: A deranged liver causes pessimism. Liver and stomach derangements cause sadness and the so-called neurasthenia. Genito-urinary affections produce irritability, jealousy, and a desire for revenge. Hypochondria and self-destruction are among the potential effects of venereal derangements. Granular inflammation and stricture of the urethra create irritability.

Delirium in fevers and drunkenness is a well-known phenomenon.

Psychical impressions are reflected on the body. Fear envy, and jealousy provoke excessive kidney, bowel, and heart action. Digestion is very seriously affected by worry. fear, or an unsatisfied state of the mind.

Nervous Reactions In The Normal State

In the normal state reactions vary; the conditions also differ.

Species

The higher the species, the more powerful the reactions. Shocks, stimulations, or irritations which cause little or no response in animals, produce suffering and sometimes fainting in man. Shock seldom occurs in animals; when it does, it is always due to violent causes. This being true, why should vivisection throw any light on the management of man's diseases?