Note 1 — Chapter I · Introduction.

The Value of Physiological Knowledge. “If any one doubts the importance of an acquaintance with the fundamental principles of physiology as a means to complete living, let him look around and see how many men and women he can find in middle life, or later, who are thoroughly well. Occasionally only do we meet with an example of vigorous health continued to old age; hourly do we meet with examples of acute disorder, chronic ailment, general debility, premature decrepitude. Scarcely is there one to whom you put the question, who has not, in the course of his life, brought upon himself illness from which a little knowledge would have saved him. Here is a case of heart disease consequent on a rheumatic fever that followed a reckless exposure. There is a case of eyes spoiled for life by overstudy. “Not to dwell on the natural pain, the gloom, and the waste of time and money thus entailed, only consider how greatly ill health hinders the discharge of all duties,—makes business often impossible, and always more difficult; produces irritability fatal to the right management of children, puts the functions of citizenship out of the question, and makes amusement a bore. Is it not clear that the physical sins—partly our ancestors’ and partly our own—which produce this ill health deduct more from complete living than anything else, and to a great extent make life a failure and a burden, instead of a benefaction and a pleasure?”—Herbert Spencer.