THE TEACHING OF PSYCHOLOGY. 333 



is in its turn divided into two parts, accordingly as it studies the 

 sound man or the diseased man. The former is physiological 

 psychology properly called, the other pathological psychology. 

 This distinction is, however, more ideal than real, because so far 

 the whole study has proceeded rather by the pathological road 

 than by the direct observation of the healthy condition ; but it is, 

 nevertheless, correct in principle. 



The matter of the new science comprises a number of facts not 

 yet connected or co-ordinated, but which have been determined, 

 to a certain extent. Among them are cerebral localizations, aphasia 

 in particular, the muscular sense, heredity, suggestion, double con- 

 sciousness, etc., besides others which have been longer known. 



The theory of cerebral localizations was suggested by Dr. 

 Gall and the phrenological school, who, however, compromised 

 it by associating it with an untenable system, for which they 

 did not offer a shadow of positive proof. Flourens approached 

 the subject in a scientific manner, with experiments on the 

 brains of pigeons, from which he deduced that the brain par- 

 ticipates in the functions of thought and feeling as a single 

 whole. He nevertheless opened the way to localizations by dis- 

 tinguishing various organs in the brain, and employing the dis- 

 tinctions of the spiritual philosophy between sensation and 

 thought, seating the latter in the brain and the former in the 

 spinal marrow. The theory of localizations has become much 

 more precise since Flourens. Not only has it been possible to 

 seat the motor functions and their various disorders with a quite 

 novel precision in their several parts of the brain and spinal cord, 

 but the mental faculties also have begun to yield to efforts to 

 localize them. Thus, the faculties of pure thought have been 

 placed in the gray matter, and the plurality of the cerebral organs 

 and the diversity of their functions appear to have been estab- 

 lished in the surest and most brilliant manner in the theory of 

 the seats of language, in which the faculties relating to speech, 

 reading, writing, and hearing are severally assigned their specific 

 quarters. In this we have one of the clearest and most precise of 

 the data of psycho-physiological science. The object of this sci- 

 ence is the determination of the physiological or organic condi- 

 tions of the mental faculties. In the present case the mental fac- 

 ulty is language ; the plurality of seats is the organic condition ; 

 and this plurality explains the singular separations that are made 

 in certain morbid cases between groups of phenomena absolutely 

 homogeneous, as, for example, between reading and writing. Yet 

 it is doubtful if we can go on to say that this explains language 

 itself in so far as it is a psychological faculty. It is a case of 

 cerebral topography and correlation, but nothing more. 



One of the most obscure and complicated questions of physio- 



