Page:The healing art in its historic and prophetic aspects - the Harveian oration delivered before the Royal College of Physicians, Oct. 19, 1885 (IA b21908199).pdf/25

 physiology. Prominent among the researches into structure was the recognition by Schwann and Schleiden of the so-called cell in all living tissues; a doctrine which has been subsequently extended to embrace the existence of protoplasmic forms generally. I need not more than mention the very considerable position, both as regards extent and accuracy, which histology has assumed within the past few years.

So long as the study of the phenomena of the living body was hampered by the dominant notion of a special vital principle, not amenable to the laws which governed inert matter, and which was to be investigated in ways other than those which were producing such grand results in the domain of chemistry and physics, the progress of physiology was likely to be slow and accidental. The turning point in the subject was undoubtedly its being brought into harmony with the principles which govern other experimental sciences, and being pursued along the same path. So far as the change can be attributed to an individual, it is to Mayer that this credit must be given, for his work in 1845 on the relation of organic motion to the exchange of material. For some time from that date, no function of the body escaped investigation by the method of direct experiment of which a mistaken humanity and senseless clamour have since deprived us; always aided by the experiments which nature offers to the physiologist in the operations of disease, complicated though these experiments be by conditions which render them more difficult of explanation.

From the chemical side physiology has received much assistance. Our knowledge of the composition of the blood and its derived secretions, though still leaving a great deal to be desired, has done something towards nnravelling the complex chemistry of the tissues. The chemistry of diges- tion and respiration, which a century, nay fifty years ago, was a jargon compounded of the residues of the Hippocratic C