PHYSIOLOGICAL SIGNIFICANCE OF VITAL FORCE. 767 



morphological complications, that the way seems prepared by nature 

 herself for the inquirer to enter the portals which open into the mys- 

 teries of life. They are on the border-land of the living and the not- 

 living, blending on the one side with colloidal matter and on the other 

 with vegetable forms, all so intimately related with simple "matter" 

 as to justify if not necessitate the conclusion of genetic correlation. 



We see this simple hyaline particle of bioplasm expand and con- 

 tract, accompanied with chemical composition and decomposition, and 

 the conclusion is irresistible that these simplest forms of motion, 

 expansion and contraction, follow in orderly sequence of cause and 

 effect. 



Motility, arising from chemical disintegration and reintegration, 

 represents, therefore, a fundamental expression of living organized 

 matter, and impresses us with the idea of energy transformed. Indeed, 

 all the functions of the higher organisms testify to the truth of the 

 proposition that every manifestation of energy of organized bodies has 

 its mechanical equivalent, and follows an orderly sequence of events. 



The nutrition of the body, through all the intricate processes of 

 external and internal digestion under the action of the digestive fer- 

 ments, involves only physical and chemical forces in the transforma- 

 tion of the various foods received. The entire animal body is com- 

 posed of modified protoplasm, as represented in the three classes 

 known as proteids, carbohydrates, and fats, with their respective 

 derivatives. 



The proteids are exceedingly complex in character, and are not as 

 yet definitely classified among organic compounds. They unite with 

 acids and alkalies, and yet " do not play the part of an acid toward 

 the base," or conversely. They are not crystallizable, and, having no 

 combining equivalent, do not possess an absolute ultimate constitution, 

 and therefore their molecular reactions and changes in the body can 

 not be expressed by exact chemical symbols. 



Here, then, we see the formidable list of " proximate principles " 

 that are known to belong to the animal body as nutrient elements, and 

 which are necessary for tissue development. They are all organic 

 compounds, from which science has "banished the vital force" by 

 "proving them to be subject to the same physical and chemical forces 

 which determine the composition of universal matter." "Where, then, 

 shall we seek this " indefinable something " which exists and acts in 

 the organism independent of and antagonistic to the physical and 

 chemical forces of nature, as affirmed by the doctrines of " vitalism " 

 taught by Stahl and Bichat ? 



The position held by these distinguished men and their followers 

 has been demonstrated to be untrue, because, whatever may be the 

 essential nature of this vital force, certain it is that it is known only 

 by and through its manifestations. These present themselves to the 

 mind only through organizations which immediately depend on chemi- 



