Page:The Harveian oration - delivered at the Royal College of Physicians, London, June 29th, 1867 (IA b22315263).pdf/26

 out the assistance of any muscular heart to propel the fluid, we are led to believe that there must be some chemical (or perhaps, more properly speaking, electrical) power which guides the movement.

Leaving this, which is still a matter of speculation, I must, however, state that we are in possession of sufficient evidence in regard to what is called osmosic action to enable us to reason upon that remarkable property of membranes, and apply it both to physiology and pathology. Of all subjects, the law of transmission of liquids and gases through membranes (known to be, in the case of fluids at least, in some inverse ratio of their densities) is that which seems to promise the most immediate application to the actual nature of the forces in the living body.

As I have just hinted, the point at which our inquiries seem to halt in the vegetable circulation relates to the movement within the cell. It seems that the interchange of gases may be the result of a similar or identical force to that of osmosic action; and thus we have a glimpse at an universal oneness of