ABSTRACT
150. The Internal Environment.—Claud Bernard defined the blood as “ the internal environment.” Indeed, the blood distributes food and oxygen to the issues, and carries away the waste products of the interorganic combustion, the cells of the body living in it as in an atmosphere. But also everything which decreases the useful elements of this internal environment, and even more so, all substances capable of vitiating it, have a serious effect on the organism. From this point of view we must consider the quantity and the quality of the aliment, as well as the rôle of the nervines and the toxic products. Life itself is an incessant evolution, whose rapidity depends on various factors: the variable activity of the subjects, their age and their sex. There are many distinct problems which merit a detailed study, but which cannot be dealt with in this book. For these the reader should consult treatises on Hygiene. This book will only sum up the ideas concerning the relations of the internal environment of man to his work.
