388 The American Naturalist. [April, 
PSYCHOLOGY." 
In his “ Introduction to Comparative Psychology,” (Contemporary 
Science Series, Walter Scott & Sons, London), Professor Lloyd Mor- 
gan’s central object is, he tells us in his preface, “to discuss the relation 
of the psychology of man to that of the higher animals...a secondary 
object...is to consider the place of consciousness in nature, the relation 
of psychical evolution to physical and biological evolution and the 
light which comparative psychology throws on certain philosophical 
problems.” s far as the formal element in his book is concerned, 
Professor Morgan makes no claim to originality. He has made use, so 
far as I can see, of three architectonic principles. The first of these 
is the symbolic conception of consciousness as a “ wave ;” the crest of 
the wave corresponds to the “ focus of consciousness,” more usually 
called the centre of attention, while the other portions of the wave 
represent the “marginal” elements, those of which we are conscious 
but to which we are not attending. The second is the conception of 
“ relations ” as “ the momentary feelings accompanying transitions in 
consciousness.” The first of these conceptions Professor Morgan credits 
to Professor James, of Harvard; the second to Mr. Spencer. The 
third principle he does not explicitly mention in his preface, probably 
because it would be difficult to ascribe it, in the form in which it is 
stated by himself and others, to any given individual. It is the con- 
ception of a selective, synthetic activity as characteristic of subject and 
object alike; this, in the object, is the activity manifested in the ob- 
jective sequences which are formulated as natural laws; in the subject 
it is that “to which the term Will is properly applicable” (page 
315). 
In the few pages of Prolegomena the doctrine of monism is briefly 
outlined, first, as the monistic theory of knowledge, second, as the 
monistic interpretation of nature, third, as a monistic analysis of 
nature into mental and material “ aspects,” distinguishable in thought 
but not separable in existence. The first three chapters preparé the 
way for the detailed discussion that follows. The conception of con- 
sciousness as a wave is made plain in chapter I; in chapter II, on the 
“ Physiological Conditions of Consciousness,” it is shown that it matters 
little whether we take as our working hypothesis the pure monistic 
1! This department is edited by Dr. Wm. Romaine Newbold, University of Penn- 
sylvania. 
