28 PROTOPLASM. 



vital force is but a property of matter." It might be objected 

 that crystalline force keeps particles still and compels them 

 to assume a constant form, while vital force prevents them 

 from assuming any definite form at all and keeps them 

 moving,; -form being assumed only when the matter is with- 

 drawn from the influence of the vital force ; but these and 

 any other objections raised to the physical theory of life are 

 accounted absurd and frivolous. It has been asserted posi- 

 tively that there is but one true theory of life the physical 

 theory. Its advocates seem to think that any objections 

 raised to this ought not to be listened to, because they 

 assert prophetically that by the rapid advance of molecular 

 physics, the truth of their theory will some day be fully 

 established. 



Aquosity and Vitality. The properties possessed by in- 

 organic compounds are supposed to be due in some way to 

 the properties of the elements of which they consist. Thus 

 it has been remarked that the properties of water result 

 from the properties of its constituent gases, and are not due 

 to " aquosity," as if any reasonable man would think of 

 referring the properties of water to such a " subtle in- 

 fluence" as " aquosity." It has been argued that since the 

 properties of water are due to its gases and not to aquosity, 

 the properties of protoplasm are due to its elements, Oxygen, 

 Hydrogen, Nitrogen, and Carbon, and not to vitality. But 

 the cases are by no means parallel. Of water there is but 

 one kind.* Of protoplasm there are kinds innumerable. 

 The constituent elements of the same particle of water may 



* A hostile critic has discovered that there are at least two kinds, 

 dirty water and clean water ! 



