Halliburton W.D. Hand-book of Physiology

9 Edition. — Philadelphia: Blakiston's Son, & Co., 1904. — 902 p.
Biology is the science that treats of living things, and it is divided into two main branches, which are called respectively Morphology and Physiology. Morphology is the part of the science that deals with the form or structure of living things, and with the problems of their origin and distribution. Physiology, on the other hand, treats of their functions, that is, the manner in which their individual parts carry out the processes of life. To take an instance : the eye and the liver are two familiar examples of what are called organs; the anatomist studies the structure of these organs, their shape, their size, the tissues of which they are composed, their position in the body, and the variations in their structure met with in different parts of the animal kingdom. The physiologist studies their uses, and seeks to explain how the eye fulfils the function of vision, and how the liver forms bile, and ministers to the needs of the body in other ways. Each of these two great branches of biological science can be further subdivided according as to whether it deals with the animal or the vegetable kingdom; thus we get vegetable physiology and animal physiology. Human Physiology is a large and important branch of animal physiology, and to the student of medicine is obviously the portion of the science that should interest him most. In order to understand morbid or pathological processes it is necessary that the normal or physiological functions should be learnt first. Physiology is not a study which can be put aside and forgotten when a certain examination has been passed ; it has a most direct and intimate bearing in its application to the scientific and successful investigation of disease. It will be my endeavour throughout the subsequent pages of this book to point out from time to time the practical relationships between physiology and pathology.