Popular Physiology.—1. A Manual of Animal Physiology, for the use of Non-medical Students.
Authors: Shea John , Lawson Henry 
Published: April 2021

ABSTRACT
The publication of two manuals almost simultaneously, devoted to the subject of physiology and for the instruction of unprofessional persons, is certainly a subject for congratulation. Of all the departments of human knowledge which the recent progress of natural science has systematised and made available for the practical use of mankind, physiology is undoubtedly the most important. It deals with the facts and laws of life—than a knowledge of which there is nothing more important to man. Just as he has gained a knowledge of the conditions that influence his life, has he become more civilised, more healthy, more moral, and more religious. In utter ignorance of the laws of life no man can live. The facts with which he becomes instinctively acquainted serve him, in his barbarous and civilised state, to maintain his existence and even increase his race ; but it is in those conditions of society where men are taught those laws of life which are the result of sufficient investigation, that we can alone anticipate the healthiest existence and the highest moral and religious development. It has been only within the present century that physiology, by embracing the statistics of life and death in large communities of men, and tracing minutely, with the aid of the microscope, the minute details of the changes which go on in the system to produce these grand results, has been in a position to claim the attention of man. It now comes forth with’ an authority which ought to compel its principles to be listened to and its precepts to be taught to all who have an interest in health and life. We would here especially suggest to those who are en-gaged in microscopic investigations into the nature of those changes which go on in the tissues of the body, that they should make the knowledge they thus gain as practical as possible. Let them not be satisfied with the beauty or the interest of minute vital changes, but let them stride to connect them with the great laws of life by which the population of the world is maintained and human health and happiness secured. Microscopical research is not an end, and the microscope is only an instrument to help the eye to investigate the more minute phenomena of matter, in whatever form it presents itself. Of all the practical directions in which a fondness for microscopic research may be made available for the benefit of the individual who makes it, and for the circle in which he moves, is that of striving to understand the laws which regulate the healthful existence of his own body. The man who acquires any kind of knowledge at the expense of health has made a poor exchange, and the highest use to which human knowledge can be applied is to gain good health and length of days. As introductions to a knowledge of the great laws of life which are already known, we can recommend the manuals named above They differ in matter and style, but they have the same object in view. Dr. Shea’s is a plain, straightforward account of the phenomena of life, and is the result of much reading and reflection ; Dr. Lawson is much more discursive, does not hesitate to introduce his own views of phenomena, and endeavours to amuse whilst he instructs. If we were asked for what class of readers they are adapted, we should say that Dr. Shea’s manual was best adapted for a class, whilst Dr. Lawson’s would be found more available for private reading and self-instruction. We will, however, endeavour to give our readers an idea of these useful little books by extracts from those portions of the books which treat of microscopical subjects. We first give an extract from Dr. Shea’s account of the blood.