INTRODUCTION. 



To begin with, the phrase : Circulatio circulationum omnia 

 circulatio, the sub-title of the following extracts, requires 

 a few words of reference or explanation. After many 

 years of observation and experience, and more or less 

 consecutive thinking and study, the truth of the above 

 generalisation has become more firmly and deeply im- 

 pressed on our mind, and, after every attempt to prove 

 its untruth and its non-applicability as an instrument of 

 research, and a physico-biological principle around which 

 can be grouped, or on which can be threaded, the fragments 

 of scientific truth as they have become available, has 

 failed, we have been compelled to admit its adaptability 

 to these purposes, and to take advantage of its services 

 in enabling us to advance from position to position, and 

 to maintain the continuity and cohesion of the course we 

 have pursued. 



Circulation, as a materio-dynamic principle, is as wide as 

 the universe, and as all-embracing as the laws of evolution 

 and involution matter, energy, and mind being alike 

 subject to its operation, and conforming to its "manners 

 and methods " in all their manifold manifestations, while 

 the working of the entire mechanism of nature, so far as 

 the understanding of a fractional portion of it warrants the 

 assumption, is alone possible on the plan from which this 

 principle derives its title. Thus, every molecule of matter, 

 every unit of energy, and every thought of mind, follow 

 each other in endless procession or circulation onwards and 

 onwards, in undeviating order and succession, one giving 

 place to the other, to the obviation of stasis, retrogression, 

 confusion, friction, or concussion, in the maintenance of 



