182 PHYSIOLOGY OF CENTRAL NERVOUS SYSTEM. 



cerebrum is concerned, the methods that he employed, although 

 perhaps the only ones that he could make use of at that time, 

 have since been demonstrated to be fallacious when used as he 

 used them. He conceived that the more developed any given 

 mental quality is the larger will be the organ representing it in 

 the cerebrum, and since the cranium fits closely to the cerebrum 

 the relative prominence of the parts of the cerebrum may be judged 

 by a study of the exterior of the skull. This method of study con- 

 stituted the essential feature of cranioscopy or phrenology, and 

 by observation upon people with particularly marked mental 

 qualities Gall and his disciples supposed that they had located the 

 organs for thirty-five different faculties. While the general idea 

 of this method may be defended, it is obvious that the application 

 of it scientifically, so that positive and demonstrable results can 

 be obtained, is practically impossible. The system of phrenology 

 and its methods quickly fell into disrepute, since they were ex- 

 ploited chiefly by frauds and charlatans. Gall's ideas in the 

 beginning excited the greatest interest, but it seems that he was 

 never able to convince the majority of the scientific men of his day 

 of the conclusiveness of his results. At the time that he was 

 teaching his doctrines in Paris, where he spent the latter years of 

 his life, Flourens began his celebrated experimental work upon the 

 functions of the brain, work which was mainly instrumental in 

 convincing physiologists that the cerebrum is a single organ, 

 functionally equivalent in all of its parts.* Flourens' chief ex- 

 periments were made upon pigeons, and in these animals he found 

 that successive ablations of parts of the cerebrum from before 

 backward or from side to side were not followed by a corresponding 

 series of defects in the animals' psychical life. On the contrary, 

 when the quantity of brain substance removed was sufficiently 

 large, all these qualities went at once. The choice of animals 

 for these experiments was an unfortunate one, but the results 

 were corroborated in part by a number of instances in which human 

 beings by accident or wounds in battle had lost a part of the brain 

 without any apparent defect in their mental powers. Therefore 

 toward the middle of the nineteenth century the prevalent view 

 in physiology was that the cerebrum is functionally equivalent in 

 all of its parts. One fact was known in medicine at that time 

 which distinctly contradicted this belief, namely, that an injury 

 to the posterior portion of the third frontal convolution in man, 

 on the left side, causes a loss of articulate speech (motor aphasia). 

 But this fact, so significant to us now, was not properly valued at 

 the time. The beginning of our modern views of- cerebral localiza- 



* Flourens, " Recherches experimentales sur les proprietes et les fonctions 

 du systeme nerveux dans les animaux vertebres," 1824. 



