1395.] Psychology. 389 
identification of the mental and physical series or the empirical dualism 
commonly known as the doctrine of parallelism. Chapter III inquires 
into the inevitable limitations of the method of analogy as applied to 
the interpretation of other minds than ours. 
In the thirteen chapters following, Professor Morgan applies himself 
to the purely psychological part of his work, and throughout, after 
devoting a chapter or two to the analysis of the phenomena of the 
human mind, he endeavors in the next chapter to determine whether 
analogous mental states are to be ascribed to animals other than man. 
He begins his inquiry with the more concrete phenomena of the spe- 
cifically inner life and concludes that in the lower animals concrete 
representative ideas are suggested by sense impressions, associated with 
one another and remembered very much as they are in ourselves. He 
then takes up the difficult problems of sense experience in the chapter 
on the “ Analysis of Impressions;” the ultimate elements of impressions 
are distinguished as sensations of various kinds; the chapter on “ Syn- 
thesis and Correlation ” then undertakes to show “ how these sensation 
elements are combined synthetically to form impressions as we know 
them ; how they enter into correlation with each other; and how they 
call up through association representations of similar sensation ele- 
ments.” Under the caption “The Sense Experience of Animals, 
Professor Morgan gives his reasons for concluding that the sense ex- 
perience of the higher vertebrates is much the same as our own, while 
of that of the lower forms of life we probably can form no representa- 
tive idea whatever. 
Chapter XI develops in sharp relief the doctrine of lower (i. e. sub- 
cortical) automatic centers standing under the control of higher (cor- 
tical) centers whose augmenting or inhibitory activity is in turn deter- 
mined by sensory (conscious) centers. The activities of these latter 
centers, again, are determined by the emotional tone associated with 
their functioning. Professor Morgan also inclines to the belief that 
special centers exist for the control of these purely sensory centers (pp. 
194-5). Chapter XII, entitled ‘Instinct and Intelligence,” applies 
these principles to the explanation of the conduct of animals, showing 
that while animals may act instinctively, their habits are for the most 
part empirically determined by the method of trial and error, and 
consequently must be regarded as fully conscious. To this method of 
trial and error Professor Morgan would restrict the term intelligence. 
Chapters XIII and XV on the “ Perception of Relations” and 
“ Conceptual Thought,” are perhaps the most suggestive in the book. 
A relation is the transition between two focal states of consciousness ; 
