

EXPERIMENTS ON THE CEREBRUM. 293 



matter. These facts, together with the utter absence of any coin- 

 cidence between the boundaries of the convolutions and the cranio- 

 graphical mapping out of the so-called organs of the phrenologist, 

 have led the most learned and influential anatomists and physiologists 

 to demur to the system originated by Gall and Spurzheim. Nor is the 

 catalogue of presumably distinct mental faculties, enumerated by the 

 phrenologists, more satisfactory to the modern school of metaphysi- 

 cians. Hence, whether the subject be regarded from a physiological 

 or from a metaphysical point of view, although it may be true, yet 

 not established, that different parts of the cerebral hemispheres exer- 

 cise certain special mental functions, still it is by no means determined, 

 either what those distinct or primal faculties or powers may be, much 

 less the locality or organs, in or by which they are actively exercised 

 in the body. 



The first noteworthy observations, made in cases of disease of the 

 cerebral hemispheres, tending towards a determination of the locality 

 of any particular faculty, have been those collected by M. Broca, in 

 reference to the faculty of language, which, according to him, has been 

 noticed to have been lost in several adult persons, who, after death 

 from paralysis, were found to have -had softening of the upper and 

 posterior part of the frontal lobe, in front of the fissure of Rolando. 

 It is a singular, and hitherto quite unexplained fact, that, in these 

 cases, the injured part was always on the left side of the cerebrum; 

 and Dr. Hughlings Jackson has since shown that this is almost an in- 

 variable rule. Much further observation is needed to clear up this 

 question, and it is yet premature to conclude that the organ of lan- 

 guage is situated in the locality found in these cases to be diseased. 



Experiments made upon animals, with the view of determining the 

 special functions of the cerebral hemispheres, throw only a most gen- 

 eral light upon this subject. The first great and fundamental fact to 

 be noted is, that the cortical substance of the cerebral hemispheres can 

 hardly be the seat of sensation, for it is itself insensible. Animals 

 exhibit no signs whatever of pain, and no muscular contractions in 

 either the muscles of animal or vegetative life, when the hemispheres 

 are superficially pricked, pinched, or cut; and even in the human sub- 

 ject, injury to this part of the brain, or removal of portions which 

 protrude after accidents to the head, does not cause local suffering, 

 even though the consciousness be perfect. Neither does injury to 

 these parts, inflicted purposely on animals, or accidentally on man, 

 cause any convulsive motion. Nevertheless, though itself insensible, 

 this cortical hemispheral matter is believed to be the place where sen- 

 sations become perceived, i. e., referred to their external causes, where 

 attention is exercised, where ideas are formed, and emotions are ex- 

 cited; where memory retains its impressions, and where the will origi- 

 nates. For in animals, when the hemispheres are mutilated, the 

 cerebral functions are disturbed; and when they are removed, those 

 functions are suspended or destroyed. Thus, when one hemisphere is 

 removed, there is produced temporary feebleness of the opposite side, 

 with a permanent blindness in the opposite eye. After partial re- 

 moval of both hemispheres, stupor is produced ; but there .soon return 



