194 



♦ KNOWLEDGE ♦ 



[March 6, 1885. 



by this very process that he hopes to bring into action the 

 full powers of this dual organ. 



He remarks that "every organ which is put in use for a 

 certain function gets developed, and more apt or ready to 

 perform that function. Indeed, the brain shows thi.s in 

 point of mere size. For the left side of the brain, which 

 is used most, is larger than the right side. The left side of 

 the brain also receives a great deal more blood than the 

 right side, because its action preponderates, and every 

 organ that acts much receives more blood. As regards 

 the influence of action on the brain, there is a fact which 

 hatters know very well. If a person is accustomed for 

 many years of adult life — say from twenty up to forty or 

 more — to go to the same hatter, the hatter will find, after a 

 time, that he has to enlarge the hat of his customer ; and, 

 indeed, a per.son advanced in years, even having passed 

 fifty-six, as I have," said Brown-Sequard, " may have a 

 chance to observe such a change. There is no period of six 

 months that has passed that I have not found my hat, if 

 neglected and put aside, has become too small. The head 

 growing is very strong proof that the brain grows also. 

 Action is a means of increasing size. It is also a means of 

 developing power. I have no doubt that a good many 

 among you have observed that, after paying great attention 

 to a subject, they have not only acquired knowledge on 

 that subject, but become much better able to solve ques- 

 tions relating to that subject — that having developed the 

 part of the brain which has been used for the acts per- 

 formed, that part has become far better able to perform the 

 duties demanded of it." 



The superior size, therefore, of the left side of the brain, 

 as well as the fact that it i-eceives a larger share of blood 

 than the right, show that it is predomiuant in our system. 

 This fact is also shown by the prevalence of right-handedness 

 among all races of men. There is no left-handed race 

 among all the races that people the world.* But also, the 

 left-handed individuals of every race have the brain corre- 

 spondingly unequal, only that in their case the right side 

 of the brain is more developed, and that side, instead of 

 the left, controls the faculty of expressing ideas, whether 

 by language or by gesture, and acts chiefly in intellectual 

 operations. The connection between greater development 

 of the brain and the control of reason, and its expression, 

 by the side of the brain so developed, seems conclusively 

 establi.shed. The side of the brain which chiefly guides 

 our actions has the greater mass of grey matter, the 

 greater number of convolutions, the most plentiful supply of 

 blood. 



Now it appears certain that the greater development of 

 the left side of the brain, and, consequently, if the infer- 

 ences just drawn are sound, the chief use of that side in 

 reason, language, and gesture, is brought about by actions 

 under the control of will. We exercise most the right side 

 of the body, hence the left side of the brain becomes 

 better developed than the right ; and hence, therefore, it 

 assumes the function of controlling intellectual processes 

 and their expression. If, of set purpose, we exercised 



* Right-sidedness extends even to lower racos, thongh there are 

 few cases in which we have the means of determining it. Birds, 

 and especially parrots, show right-sidedness. Dr. W. Ogle has 

 found that few parrots perch on the left leg. Now parrots have 

 -that part at least of the faculty of speech, which depends on the 

 memory of successive sounds, and of the method of reproducing 

 such imitation of them as a parrot's powers permit ; and it is re- 

 markable that their left brain receives more blood and is better 

 developed than the right brain. So far Dr. Brown-Sequard on this 

 point. It may be questioned whether monkeys show any tendency 

 to right-handedness; my own recollections of monkey gestures 

 certainly suggest no preference of the kind. Here is a field for 

 observation and inquiry among our zoological professors. ■,,:.,. ^ 



equally both sides of the body, if in particular we employed 

 the organs on the left side in processes at present chiefly 

 or wholly managed by those on the right, would not the 

 two sides of the brain become equally developed, and might 

 not both become capable of controlling the reasoning facul- 

 ties ? On this point we have evidence which is well worth 

 considering, even if it cannot be regarded as decisive. 



Cases have occurred in which the left side of a child's 

 brain has become diseased before the child has learned to 

 talk. In such cases the child has learned to talk as well, 

 or nearly as well, as if the left side of the brain had been 

 sound. Now, if in such cases the child had been born of 

 left-handed parents, we could regard the result as depend- 

 ing on the hereditary transmission of^exceptional powers to 

 the right side of the brain. But no such explanation has 

 been available. In most instances, certainly (in all accord- 

 ing to Brown-Sequard's belief), the parents of these children 

 were right-handed. In fact, the circumstance that these 

 children, besides being able to speak, could make use of all 

 the members on the right side of the body (though the left 

 side of the brain, which usually controls the movements of 

 those members, was diseased), shows that the right side of 

 the brain had assumed powers not ordinarily belonging to 

 it. The children, however, as might be expected, were 

 left-handed, the left side of the body being governed as the 

 special province of the right brain, and the right side only 

 because the disease of the left brain forced on the right 

 brain the duty of governing the right side of the body, as 

 well as that of controlling reason, speech, and gesture. 



(To he continued.) . ' '\ ' 



THE 



FORTHCOMING PHOTOGRAPHIC 

 EXHIBITION. 



SCIENTIFIC research of almost every kind owes so 

 much to photography for its successful issue, that any 

 attempt to increase the popularity of the art should meet 

 with ready recognition at the hands of all who are inte- 

 rested in the progress of science. It is no exaggeration to 

 say that some of the most important scientific discoveries 

 could never have been eflected without the help of 

 the camera. It has enabled the astronomer to do much 

 towards the solution of the mystery of the heavens ; and 

 Professor Draper and Dr. Huggins have already succeeded 

 in determining by its aid some of the elements contained 

 in " other worlds," whose distance from us is so great 

 that it has taken their light, travelling 180,000 miles per 

 second, thousands of years to reach us. 



In conjunction with the microscope, too, photography is 

 of incalculable importance in the study of the " ills that 

 fle.sh is heir to," a notable instance of which may be found 

 in the assistance the camera has afforded to Dr. Koch in 

 his world-renowned bacilli researches ; and many of the 

 results pertaining to medical jurisprudence, in the detec- 

 tion of crime, have been largely obtained through the same 

 medium. 



Again, photography is of no less importance to the 

 meteorologist, as, by means of a specially-constructed 

 camera, it has been found possible to obtain photographs 

 of the forms and dispositions of clouds, the comparison 

 of which is so necessary in connection with attempted 

 weather prognostication. In a word, almost every branch 

 of scientific study has been, and is likely still further to 

 be, largely indebted to photography ; therefore, we say 

 again that any means which can be devised for lifting that 

 art out of professional grooves — where it is necessarily 

 stilted in its operations — should be welcomed by all to 



