The force of sensations and impressions depend upon the condition of the nervous tissue. A change in the structure or position of an organ creates over or under, too much or too little, function, a condition known as disease. There is a difference between disease is the result of over or under function and over or under function is disease. Functions performed normally is health, in an abnormal manner or amount is disease, a departure from a state of health. Physiology treats of functions performed normally.
Pathology discourses upon functions performed in an unusual manner.
The performance of functions depend upon the amount of energy stored and aroused by innervation. Pathological physiology is the performance of functions by an excess or a deficiency of vital force. Teratology is the science of abnormal growths, the result of vegetative functions performed in an abnormal and unusual amount. Vitality runs the vegetative function, while intellectuality directs the cumulative function. As the vegetative function may produce teratism, even so, the cumulative may accumulate monstrous intellectual conceptions.