Introduction, 



The Scope of Physiology and its Kelations to'. other Branches 

 of Natural Science. 



Physiology is the science of the vital phenomena of organisms, or, broadly, it is 

 the Doctrine of Life. Correspondingly to the divisions of organisms, we distinguish 

 (1) Animal Physiology ; (2) Vegetable Physiology ; and (3) the Physiology of 

 the Lowest Living Organisms, which stand on the border line of animals and 

 plants, i.e., the so-called Protistse, of Haeckel, micro-organisms, and those elementary 

 organisms or cells which exist on the same level. 



The object of Physiology is to establish these phenomena, to determine their 

 regularity and causes, and to refer them to the general fundamental laws of 

 Natural Science, viz., the Laws of Physics and of Chemistry. 



The following Scheme shows the relation of Physiology to the allied branches of 

 Natural Science : 



BIOLOGY. 



The science of organised beings or organisms (animals, plants, protista?, and 

 elementary organisms). 



I. Morphology. 

 The doctrine of the form of organisms. 



General Special 



Morphology. Morphology. 



The doctrine of the The doctrine of the 



formed elementary parts and organs of 



; constituents of or- organisms. 



ganisms. (Organology 



(Histology) Anatomy) 



(a) Histology of Plants, (a) Phytotomy. 



(b) Histology of Animals. (6) Zootomy. 



II. Physiology. 

 The doctrine of the vital phenomena 

 of organisms. 



General 

 Physiology. . 

 The doctrine of vital 

 phenomena in gene- 

 ral 

 (a) Of Plants. 

 (&) Of Animals. 



Special 

 Physiology. 



The doctrine of the 

 activities of the in- 

 dividual organs 



(a) Of Plants. 



(b) Of Animals. 



III. Embryology. 



Jhe doctrine of the generation and development of organisms. 



( 1. History of the development of ^ 

 single beings, of the individual 

 (e.g., of man) from the ovum 

 onwards (Ontogeny) 



(a) In Plants. 



(b) In Animals. 

 2. History of the development of 



a whole stock of organisms from 

 the lowest forms of the series 

 upwards (Phylogeny) 



(a) In Plants. 



(b) In Animals. J 



Morphological part of the 

 doctrine of development, 

 i.e., the doctrine of form 

 in its stages of develop- 

 ment 



(a) General. 



(b) Special. 



Physiological part of the 

 doctrine of development, 

 i.e., the doctrine of the 

 activity during develop- 

 ment 



(a) General. 



(b) Special. 



