CHAPTER II

NO SHARP LINE OF DEMARKATION BETWEEN HEALTH AND DISEASE.--THE
FUNCTIONAL NUTRITIVE AND FORMATIVE ACTIVITIES OF CELLS.--DESTRUCTION
AND REPAIR CONSTANT PROCESSES IN LIVING MATTER.--INJURIES TO THE
BODY.--THE EFFECT OF HEAT.--THE ACTION OF POISONS.--THE LESIONS OF
DISEASE.--REPAIR.--THE LAWS GOVERNING REPAIR.--RELATION OF REPAIR TO
COMPLEXITY OF STRUCTURE AND AGE.--THE RESERVE FORCE OF THE BODY.--
COMPENSATORY PROCESSES IN THE BODY.--OLD AGE.--THE DIMINUTION OF
RESISTANCE TO THE EFFECT OF THE ENVIRONMENT A PROMINENT FACTOR IN OLD
AGE.--DEATH.--HOW BROUGHT ABOUT.--CHANGES IN THE BODY AFTER DEATH.--
THE RECOGNITION OF DEATH.


There is no sharp line separating health from disease; changes in the
tissues of the same nature, or closely akin to those which are found
in disease, are constantly occurring in a state of health. The
importance of parasites in causing disease has led to the conception
of disease as almost synonymous with parasitism; but it must be
remembered that the presence of parasites living at the expense of the
body is perfectly consistent with a state of health. Degeneration,
decay and parasitism only become disease factors when the conditions
produced by them interfere with the life which is the normal or usual
for the individual concerned.

All the changes which take place in the cells are of great importance
in conditions of both health and disease, for life consists in
coördinated cell activity. The activities of the cells can be divided
into those which are nutritive, those which are functional and those