Whilethesestudiesofthestructureofthecordhavebeengoingon，theingeniousandindefatigableBrown-Sequardhasbeeninvestigatingthefunctionsofitsdifferentpartswithequaldiligence。Themicroscopicanatomistshadshownthattheganglioniccorpusclesofthegraymatterofthecordareconnectedwitheachotherbytheirprocesses，aswellaswiththenerve-roots。M。Brown-Sequardhasprovedbynumerousexperimentsthatthegraysubstancetransmitssensitiveimpressionsandmuscularstimulation。Theobliqueascendinganddescendingfibresfromtheposteriornerve-roots，joiningthe“longitudinalcolumnsofthecornua，“accountfortheresultsofBrown-Sequard’ssectionsoftheposteriorcolumns。Thephysiologicalexperimenterhasalsomadeitevidentthatthedecussationoftheconductorsofsensitiveimpressionshasitsseatinthespinalcore，andnotintheencephalon，ashadbeensupposed。
Notlessremarkablethantheseresultsarethefacts，whichIwithothersofmyaudiencehavehadtheopportunityofobserving，asshownbyM。Brown-S6quard，oftheartificialproductionofepilepsyinanimalsbyinjuringthespinalcord，andtheinductionoftheparoxysmbypinchingacertainportionoftheskin。Iwouldalsocallthestudent’sattentiontohisaccountoftherelationsofthenervouscentrestonutritionandsecretion，thelastofwhichrelationshasbeenmadethesubjectofanextendedessaybyourfellowcountryman，Dr。H。F。CampbellofGeorgia。
ThephysiologyofthespinalcordseemsasimplematterasyoustudyitinLonget。TheexperimentsofBrown-Sequardhaveshowntheproblemtobeacomplexone，andraisedalmostasmanydoubtsastheyhavesolvedquestions；atanyrate，Ibelievealllecturersonphysiologyagreethatthereisnopartoftheirtasktheydreadsomuchastheanalysisoftheevidencerelatingtothespecialofficesofthedifferentportionsofthemedullaspinalis。Inthebrainwearesurethatwedonotknowhowtolocalizefunctions；inthespinalcord，wethinkwedoknowsomething；buttherearesomanyanomalies，andseemingcontradictions，andsourcesoffallacy，thatbeyondthefactsofcrossedparalysisofsensation，andtheconductingagencyofthegraysubstance，IamafraidweretainnocardinalprinciplesdiscoveredsincethedevelopmentofthereflexfunctiontookitsplacebySirCharlesBell’sgreatdiscovery。
BythemannerinwhichIspokeofthebrain，youwillseethatIamobligedtoleavephrenologysubJove，——outinthecold，——asnotoneofthehouseholdofscience。Iamnotoneofitshaters；onthecontrary，Iamgratefulfortheincidentalgoodithasdone。IlovetoamusemyselfinitsplasterGolgothas，andlistentotheglibprofessor，ashediscoversbyhismanipulations“Allthatdisgracedmybettersmetinme。“
Ilovedofoldtoseesquare-headed，heavy-jawedSpurzheimmakeabrainfloweroutintoacorollaofmarrowyfilaments，asVieussenshaddonebeforehim，andtohearthedry-fibredbuthuman-heartedGeorgeCombeteachgoodsenseunderthedisguiseofhisequivocalsystem。Butthepseudo-sciences，phrenologyandtherest，seemtomeonlyappealstoweakmindsandtheweakpointsofstrongones。Thereisapicaorfalseappetiteinmanyintelligences；theytaketooddfanciesinplaceofwholesometruth，asgirlsgnawatchalkandcharcoal。Phrenologyjuggleswithnature。Itissoadjustedastosoakupallevidencethathelpsit，andshedallthatharmsit。Itcrawlsforwardinallweathers，likeRichardEdgeworth’shygrometer。