TRANSACTIOMS OF THE SECTIONS. 131 



siology will not advance in this country so rapidly as we could wish. I would not 

 in this place have alluded to a question concerning- medical education, but for the 

 fact that the progress of physiology will always greatly depend upon the education 

 of medical men ; for only those who are conversant with physics and chemistry, and 

 who, in addition, are acquainted with the phenomena of disease (that is to say with 

 abnormal physiological conditions) can handle physiology in all its branches. Phy- 

 siology owes not a little to a study of pathology— that is, of abnormal physiological 

 states. The study of a diseased condition has on several occasions given a clue to 

 the discovery of "the function of an organ. Nothing was known regarding the 

 function of the spleen until the pathologist observed that an increase in the number 

 of white corpuscles in the blood is commonly associated with an enlargement of 

 this organ. Hence arose the now accepted doctrine tliat the spleen is concerned in 

 the formation of blood-corpuscles. The key to our knowledge of the functions of 

 certain parts of the brain has also been supplied by a study of the diseased condi- 

 tions ot that organ. The very singular tact that the right side of the body is 

 governed by the left, and not by the right, side of the brain, was ascertained by 

 observing that palsy of the right side of the body is associated with certain diseased 

 conditions of the left side of the brain ; that the corpus striatum is concerned in 

 motion, while the optic thalamus is concerned in sensation, and that intellectual 

 operations are manifested specially through the cerebral hemispheres, are conclusions 

 which were indicated by the study of diseased conditions. Moreover, by the pur- 

 suit of the same line of 'inquiry, the key has been given to the discovery of many 

 other facts regarding the brain functions. Some years ago M. Broca made the 

 remarkable observation that, when a certain portion in the front part of the left 

 side of the brain becomes disorganized by disease, the person loses the power of 

 expressing his thoughts by words, either spoken or written. He can comprehend 

 what is said to him, his organs of articulate speech are not paralyzed, and he 

 retains his power of writing, for he can copy words when told to do so ; but when 

 he is asked to give expression to his thoughts by speaking or by writing, or even 

 to tell his name, he is helpless. With a palsy of a portion of his brain, he has lost 

 his power of finding words; but although he has lost this power, his intelligent 

 perception of what passes around him and what is said to him is not lost. It is 

 true that this condition of aphasia, as it is termed, has been found to exist when 

 various parts of the brain have been diseased ; for example, it has been found to co- 

 exist with a diseased state of the posterior instead of the anterior part of the cere- 

 brum. This fact renders it very difficult as yet to assign a precise locality to the 

 faculty of speech. It is not, however, my intention to discuss this question, for iny 

 object is merely to show how the studv of disease has given a clue to the physio- 

 logist. Broca's observation led to the" thought that, after all, the dreams of the 

 phrenologists would be realized, in so far as they supposed that the various mental 

 operations are made manifest through certain definite territories of the brain. 



It has until lately been supposed that the convolutions of tlie cerebruui are 

 entirely concerned in purely intellectual operations ; but this idea is now rendered 

 doubtful. It is probable, from recent researches, that in the cerebral convolutions 

 (that is, in the part of the brain which was believed to minister merely to intel- 

 lectual manifestations) there are nerve-centres for the production of voluntary 

 muscular movements in various parts of the body. It has always been taught that 

 the convolutions of the brain, unlike nerves in general, cannot be stimulated by 

 means of electricity. This, although true as regards the brains of pigeons, fowls, 

 and perhaps other birds, has been shown by Fritsch and Ilitzi^ to be untrue as 

 regards mammals. These observers removed the upper portion of the skull in the 

 dog, and stimulated small portions of the exposed surface of the cerebrum by means 

 of weak galvanic currents ; and they found that when they stiinulated certain 

 definite portions of the surfixce of the convolutions in the anterior part of the 

 cerebrum, movements are produced in certain definite groups of muscles on the 

 opposite side of the body. By this new method of exploring the functions of the 

 convolutions of the brain, these investigators showed that, in certain cerebral 

 convolutions, there are centres for the nerves presiding over the muscles ot 

 the neck, the extensor and adductor muscles of the forearm, for the flexor and ro- 

 tator muscles of the arm, the muscles of tlie foot, and those of the face. They, 

 1873. •' 



