Biology, the science which deals with living beings, may be divided into two branches, viz. : : 1. MORPHOLOGY, which treats of the forms and structure of living creatures; and, 2. PHYSIOLOGY, which attempts to explain the modes of activity exhibited by them during their lifetime, and may therefore be defined as the science which investigates the phenomena presented by the textures and organs of healthy living beings; or, in short, the study of the actions of organisms in contradistinction to that of their shape and structure. The organic or living world is naturally divided into the Animal and Vegetable kingdoms. We have, therefore, both animal and vegetable morphology and physiology. In studying the vegetable kingdom, the form and structure as well as the activity of plants are associated together to form the subject known as Botany. The physiology of plants need not, therefore, be considered here; though, indeed, a knowledge of it proves useful in considering many of the processes belonging to animal life. On the other hand, the morphology and the physiology of animals are commonly taught separately, and in the medical curriculum are made distinct subjects. Morphology includes the external form, the general construction or anatomy of organisms, and the minute structure of their textures as revealed by the microscope. This latter branch of |