National Academy of Sciences. 



THE LOCALIZATION OF CENTERS OF MOTION IN THE 



BRAIN. 



Wo shall now take up the question of the localization 

 of motion in oertaia parts of tho brain. I am surprised 

 at the avidity with which a certain scries of facts have 

 been accepted as proof of mis Theory in England. A 

 very eminent man, of -whom I slioul I not like, to say 

 anything- seven-, my I'rieu I Pro!'. Carpenter, Ins ac- 

 cepted thoso views. I may say that all England has 

 accepted them. Prof. Huxley indeed has written me 

 that he only accepted this view in part; hut I cannot 

 6eo hnw he can accept <t part without, accepting 

 the whole, where even the part is incorrect. The famous 

 experiments of Dr. Furrier of Guy's Hospital must hero 

 be considered. As you will see, (hey are nor, however, 

 conclusive. By the application of galvanism to certain 

 parts of the brain of animals, lie produced certain move - 

 meats. When we do not stop to think, this would seem 

 to prove that there are in the hr.iiu certain centers of 

 movement governing certain part3. But it is only a 

 semblance. A part of the facts ara taken for the whole, 

 We should know all the series before we adopt the con- 

 clusions. L?t us examine the other facts. 



It is perfectly well known that the cutting away of a 

 large portion of the brain does not produce the least 

 alteration of voluntary movement anywhere. Suppose 

 that part of the brain .say the anterior lobe, beiusr ex- 

 cited by galvanism, produces a movement in the anterior 

 limb. Now suppose that part of the brain is cut away- 

 then the anterior limb should be paralyzed, for its 

 voluntary movement is gone. Admitting 1 that the 

 other half of the brain should supply the place 

 of the missing,- part ; let us take that away 

 also. Then certainly there should be a paralysis of the 

 anterior limbs. But there is not. This should be suf- 

 ficient to invalidate the conclusions of Dr. Ferrier. But 

 there are abundant pathological facts of this nature, 

 proving the fact beyond question. And then there are 

 the cases of recovery from paralysis. There is no such 

 localization of power as Dr. Ferrier has assumed. If 

 galvanism be applied (o the severed leg of the frog, the 

 leg will jump, though there is no brain posver m the 

 question. 



What should have been clone was to have cut the con- 

 nection of parts, so that a general effect should not have 

 been propagated throughtout the brain by the applica- 

 tion of galvanism to a part. Tliis would be the cxpai- 

 mcntuin cruris. My friend Dr. Dupr6 of Paris has made 

 this experiment. I made it also, before he did, but he 

 published his before mine. But ^thcre are many other 

 facts almost equally impressive in their char- 

 acter which may be cited. We find many 

 cases where the lesion of part of the brain 

 produces paralysis on the same side of the body, and not 

 on the opposite side as in the majority of cases is the 

 rule. There is a case where a ball passed directly 

 through the brain and it produced paralysis on the 

 right side instead of the opposite side. Hero Dr. 

 Brown-Sequard objected to having a certain class of 

 brain affections named after him ; stat^ig that diseases 

 should be named from, their distinctive features and not 

 after physicians. 



Dr. Brown-Seq.uard then applied a similar course of 

 reasoning to the localization of sensation in specific 

 parts of the brain, using, among other happy 

 illustrations. this fact: An intestinal worm 

 will occasion sometimes convulsive movements, 

 eometimes paralysis, sometimes deficient sensa- 

 tion; are we therefore to conclude that in these cases 

 the center of power waa iu tho abdomen. 1 He 



attacked the view of Gall, saying tint, wo do 

 not know tho locality of these affections, and 

 have no reason to suppose that they originate 

 in a limited area of the brain. AVe now know I Hat only 



a few fibers are IK s-iary to make, I be connection 



between the spinal column and tho brain. T.ie brain, 

 like the rest of the body, receives nerve fibers coming 

 from other nervous centers, soni's iiloiig tho blood- 

 vessels, for there are a great number oi libers starting 



along the blood vessels and going into tl e'lular ;l<s ie 



of tho brain; some libers coming from I lie symiuthet jc. 

 nerve; others coming from various sources. AVe flii'l, 

 for instance, that the prick of an exceedingly flue neeill 

 at the crux ccrcbclh will produce rotary movements, 

 the animal whirling around with a rapidity impossible 

 in a normal condition. Tho activit}' of the heart may be 

 stopped by the prick of a needlepoint; convulsions may 

 be similarly stopped by the action of carbonic- acid on 

 the mucous membrane of the throat. With these facts 

 under consideration we may see the vast ii.-hl of research 

 that yet lies before us, the mere qn -stious arising from 

 the activity of nerve cells affording an almost boundless 

 subiect for inquiry. But it is evident that wo cannot 

 locate the centers of either sensation or motion in speci 

 fie parts of the nervous system. 



OBSERVING THE TRANSIT OF VENUS. 



BY PROF. SIMON NEWCOMB OF THE WASHINGTON 

 OBSERVATORY. 



This was a description of the preparations 



in this country for the great astronomical event of 

 next December. Tlio first steps in respect to the ob- 

 servations on the Transit of Venus were taken 

 in Washington four years ago. Tuo plan adopted 

 divided itself into three parts; tho nature 

 of the observations; the stations to be chosen, and the 

 organization of the paities of observers. The funda- 

 mental idea of the methods adopted was then stated. 

 The two classes of determinations wore, on the one 

 hand, observations of interior and exterior contact, and 

 on the other, measurements between the centers of the 

 bodies observed. There are also the visual method and 

 the photographic method. 



Hitherto the visual method, however employed, has 

 proved very uncertain. It is now ab'iut 200 vears since 

 Halley observed a transit of Venus at th Q Island of St. 

 Helena. The absolute accuracy of his observations can- 

 IIOD now be accepted. Tho difficulty is in Knowing 

 the ex;tct moment of the ingress or egress of tho 

 planet from the sun's disk. Tho approach of the two 

 points or litrht when the planet cuts the disk of the sun 

 is a matter not only of the most delicate observation, if 

 is a point in which an intrinsic uncertainty is involved. 

 Even at the last transit of Mercury, observers dill' -red 

 enormously in noting tne time of disappear nice of the 

 dark line of sky which separated that planet from tho 

 sun. 



DIFFICULTIES IN OBSERVING A TIIANSIT. 



The best way to ascertain the conditions of this 

 phenomenon is by the observation of the transit of an 

 artificial Venus over an artificial HUH. This was done, 

 rather more than a year ago, at the high point visible 

 from tho Observatory. Tho artificial s:iu and planet, 

 were placed on Wilder'a Imildinir, at a distance, of s,300 

 feet, in order that full cll'-ct ink-lit bo given 

 to atmospheric vapors and softening.? of the 

 outline. The apparent dimensions <>f the artificial 

 sun and planet were those that will be presented by tho 

 real bodies at the tiiuu of the transit. It is found that 



