The physiology of common life

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Preface

The object of the following Work differs from that of all other works on popular science in its attempt to meet the wants of the Student, while meeting those of the general reader, who is supposed to he wholly unacquainted with anatomy and physiology. The many excellent Treatises which exist are only suited to the advanced student ; they assume a knowledge, and a facility of apprehension, which can only issue from a practical familiarity with the subjects.

The remembrance of my own wants and difficulties led me, many years ago, to the belief that the work which was really the most suitable for general culture, would also be of material assistance to the Student. Accordingly, although there are many topics, interesting and important to the physiologist, which find no place in this work, because they are without the range of general culture, I have done my best to render . the exposition, of all the topics selected, on a level with the science of our day.

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PREFACE.

In pursuance of this object I have been forced to depart very widely from the practice of other popular writers, who consider themselves bound to act as “middle-men” between scientific authorities and the public, and to expound facts and doctrines as they find them. I could not adopt this easy and convenient plan. I could not bring myself to publish, on the authority of respected names, statements which I knew to be false, and opinions which I believed to be erroneous. After having laboured earnestly to get at the truth, it would have been disloyal to contribute in any way to the spread of what I believed to be error. All that I felt bound to do, was to state impartially the facts and opinions current among physiologists ; and, when those opinions seemed inadmissible, to state the reasons for their rejection. There is therefore a great deal of criticism, and much original matter in this work.

It is in the chapters on the Nervous System that the greatest amount of dissent from current opinions will be found ; and it is there that the reader will most probably feel the greatest difficulty in agreeing with me, especially if he be versed in the doctrines of the schools, and not very familiar with the subjects through direct observation and experiment. I can only say that the views there put forth are the result of very considerable research, embracing molluscs,

PREFACE.

VI 1 bees, beetles, spiders, locusts, crabs, fisbes, frogs, tritons, lizards, chickens, moles, mice, rats, cats, dogs, sheep, pigs, calves, oxen, and men.

The literature of each subject has been given with as much fulness as seemed useful ; and never at secondhand, unless specially acknowledged. The deficiencies in this respect will be found greatest in the English department ; the reason of which is that my purse is not long enough to command the Transactions, Journals, and Reviews in which my countrymen have recorded their labours ; and 1 have not the advantage of commanding a public library. It has been my desire to render every one his due ; but of course a great many claims have been passed over in ignorance.

March 1860.

CONTENTS OF THE SECOND VOLUME.

CHAPTER VIII.

FEELING AND THINKING.

Object and scope of the inquiry — Psychology and Physiology two separate sciences — The Brain not the exclusive organ of the Mind : the two established doctrines — What is nerve force ? — Structure of the Nervous System — Are nerves conductors only, and what do they conduct ? — Error of likening nerves to the conducting-wires of a battery — Independent action of nerves — Neurility the property of a nerve — Sensibility the property of a nerve-centre — The distinction between property and function — Refutation of the supposed distinction between sensory and motor nerves — Where is the Sensorium ? — Opinions of elder writers ; modem opinions — Proof that Sensibility depends on histological, not on morphological structure, and that all nerve-centres possess it — Sensibility, Sensation, and Consciousness — Ambiguities of language : different meanings of “ Consciousness ” — Can there be sensations of which we are unconscious ? — Sensation and Perception — Unperceived sensations — The Law of sensibility — Reflex actions and Reflex feelings — Sensations unattended to in reverie and sleep — Illustrations of sleepers being conscious of sensations — General consciousness : Systemic Sensations : the feeling of existence — Systemic-consciousness, Sense-consciousness, and Thought - consciousness — Note to Chapter VIII., 1

CHAPTER IX.

THE MIND AND THE BRAIN.

Section I.— The Cerebrum

Recapitulation — Prejudice respecting the Brain as the sole organ of the Mind — Three sources of our knowledge : Experiment, Disease, Comparative Anatomy — Description of the Brain — Evidence of Comparative Anatomy against the idea of the Brain as the sole seat of sensation and

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will — Nervous systems of Mollusc and Beetle compared — Weight of the Brain — The convolutions ; are they the seat of intelligence ? — Functions of the Cerebrum — Effect of pressure on the Brain : curious case — The researches of Flourens — State of Animals when the Cerebrum is removed — Persistence of sensation and volition after removal of the Cerebrum — Experiments of Flourens, Bouillaud, Longet, and Dalton — Relation of the Cerebrum to the nerves — Forms of Sensibility peculiar to the Cerebrum— Intellect and Emotion — How can identical convolutions have different functions? — Phrenology — Explanation of the difficulty— Relation of the Intellect to the Senses, and of the Emotions to the Viscera— Other functions of the Cerebrum, 81-120

CHAPTER IX.