An Introduction to Biophysics

PREFATORY NOTE

THIS book makes no pretensions to be a complete or even a systematic survey of Biophysics. Its object is partly to be explanatory. Current medical publications are full of terms culled from physico-chemical and physical terminology; the clinician of to-day clothes his ideas in words unknown to his brethren of yesterday; his phraseology, at least, is physical.

Apart from and beyond a mere explanation of physico-chemical terms, an attempt has been made in the following pages to present physiological phenomena from a purely physical standpoint. The problems of life, and vertebrate life in particular, have been viewed through a physicist's eyes. This does not necessarily imply that the matter of the book is permeated with mechanistic philosophy. We are all, more or less, amateur philosophers, but we would be poor scientists indeed if our "views" were permitted to colour our facts. Phenomena, as they appear to-day, are set out for the critical examination of the student. "He will have all the facts and circumstances fully mobilised, standing up side by side before him like an awkward squad, and there is nothing more awkward than some facts that have to stand out squarely in the daylight! And he inquires into their ancestry, makes them hold out their tongues, and pokes them once or twice in the ribs, to make sure that they are lively and robust facts capable of making a good fight for their lives. He never likes to see one thing too large. lest he sees something else too small; but will have everything in true proportion." (David Grayson.)

It is a great pleasure to me, on reading over the final proofs, to notice how generously my masters and colleagues have come to my aid. Quite apart from the direct help given me by Professors Noël Paton and E. P. Cathcart, who contribute the opening and closing chapters of the theoretical part of the book, I have received daily encouragement from them in my task, for which I express my sincere gratitude. If this effort to make plain the

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essentials of Biophysics is in any way successful it is due to the truly scientific atmosphere of the Institute of Physiology which they govern and inspire.

I beg to record my obligation to Dr. Shanks for the care he has devoted to the chapter on the eye; to Dr. Morris for reading the first three sections of the book in slip-proof; to Dr. Watt, Lecturer on Psychology in this Institute, for reading the chapters on Receptors and for his suggestions thereon; to Dr. Wishart, because, by reading many of the proofs and by checking mathematical matter, he has saved me from many a fault and blunder.

My debts to previous authors are many and I cannot own them all. Discerning readers will see, for example, the ideas of my old teacher, Professor Soddy, mirrored in certain of the earlier chapters; Professor Thompson's Growth and Form is the basis of part of Chapters XVI., XXIV. and XXXIV. ; McKendrick, Gray, Wrightson, Keith, and Watt are the sources from which much of Chaps. XIX. and XXIX. have been drawn. A book of this nature could not be written without constant reference to the Principles of General Physiology. If my Introduction but serves to turn some student to the great book of Professor Bayliss, to meet the master mind, it will have succeeded. I am under obligation to the authors and publishers of several books from which illustrations have been borrowed.

To Professor Noël Paton and Messrs. Green for permission to use eight figures from the Essentials of Human Physiology (viz. Figs. 25, 27, 58, 59, 69, 72, 73 and 85); to Professor Starling and Messrs. Churchill for the following figures from Principles of Human Physiology: 1, 5, 8, 16, 35-41, 43, 45, 50, 70, 74, 75, 80 and 83; to Mr. Crowther for Fig. 21 from Molecular Physics, and to Mr. Emil Hatschek for Figs. 7, 9 and 10 taken from An Introduction to the Physics and Chemistry of Colloids, both books from Messrs. Churchill.

To Professor Cushny for leave to reproduce the ideal diagram of a Malpighian corpuscle (Fig. 28) from his monograph on The Secretion of Urine (Messrs. Longmans, Green and Co.); to Professor Soddy and "The Electrician " Publishing Co., for the diagram of the gold-leaf electroscope (Fig. 22) from Radioactivity.

To Dr. Bradford for allowing me to reproduce, from the Biochemical Journal, his photograph of adsorptive stratification (Fig. 11) and to Professor Roaf for the pH-C,, graph reproduced from the Proceedings of the Physiological Society (Fig. 84).

PREFATORY NOTE

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To Messrs. the Cambridge and Paul Scientific Instrument Co. for the figures illustrating the electro-cardiograph (Figs. 64-67); to Messrs. Hawksley for those of the viscosimeter (Figs. 77 and 82) and to Messrs. Gallenkamp for Figs. 2 and 3 of the bomb calori

meter.

The remaining forty illustrations were drawn by Dr. G. M. Wishart, Assistant in the Department of Chemical Physiology, and by Mr. John Waters, a student of medicine here. To their skill and care I owe much.

I am greatly obliged to Mr. A. V. Steen, B.Sc., one of our demonstrators, for reading all the proofs. The freedom of the matter from certain errors is the result of his painstaking efforts.

Finally, I desire to record my gratitude to my publishers for their patience and courtesy during the prolonged period of publication and to the printers for the care they have taken and the consideration shown when my ignorance made large demands on their time and patience.

INSTITUTE OF PHYSIOLOGY,

UNIVERSITY OF GLASGOW.

CONTENTS

INTRODUCTION. By Professor D. Noël Paton, M.D., LL.D., F.R.S.