Cell Theory and the Constitution of the Individual

Since the beginning of the nineteenth century a growing number of philosophers, naturalists, and medical doctors have referred in their written work to living matter, organic molecules, animated material, organs, and tissues, but nowhere are these terms clearly defined. In the case of higher animals, one can distinguish the flesh, bones, fat, nerves, tendons, blood vessels, membranes; what do these substances consist of? Knowledge of this subject is limited to the comments about fibers that anatomists make in their descriptions of the muscles and nerves. An eminent physician, Pinel, tried to apply the methods used by naturalists to a classification of maladies and found that this revealed a relationship between the progress of various kinds of inflammation and the nature of the membranes in which they are situated. This aroused the interest of doctors who wanted to learn more about these membranes and their relationships to the various parts of the human body.