thesesimpleformulaebywhichwecondensetheobservationsofagenerationinasingleaxiom；theselogicalanalysesbywhichwefenceouttheignorancewecannotreclaim，andfixthelimitsofourknowledge，——allleadusuptotheinspirationoftheAlmighty，whichgivesunderstandingtotheworld’sgreatteachers。Tofearscienceorknowledge，lestitdisturbouroldbeliefs，istofeartheinfluxoftheDivinewisdomintothesoulsofourfellow-men；forwhatissciencebutthepiecemealrevelation，——uncovering，——oftheplanofcreation，bytheagencyofthosechosenprophetsofnaturewhomGodhasilluminatedfromthecentrallightoftruthforthatsinglepurpose？
Thestudieswhichwehaveglancedatarepreliminaryinyoureducationtothepracticalartswhichmakeuseofthem，——theartsofhealing，——surgeryandmedicine。Themoreyouexaminethestructureoftheorgansandthelawsoflife，themoreyouwillfindhowresolutelyeachofthecell-republicswhichmakeuptheEpluribusunumofthebodymaintainsitsindependence。Guardit，feedit，airit，warmit，exerciseorrestitproperly，andtheworkingelementswilldotheirbesttokeepwellortogetwell。Whatdowedowithailingvegetables？Dr。Warren，myhonoredpredecessorinthischair，boughtacountry-place，includinghalfofanoldorchard。AfewyearsafterwardsIsawthetreesonhissideofthefencelookingingoodhealth，whilethoseontheothersidewerescraggyandmiserable。Howdoyousupposethischangewasbroughtabout？BywateringthemwithFowler’ssolution？Bydiggingincalomelfreelyabouttheirroots？Notatall；butbylooseningthesoilroundthem，andsupplyingthemwiththerightkindoffoodinfittingquantities。
Nowamanisnotaplant，or，atleast，heisaverycuriousone，forhecarrieshissoilinhisstomach，whichisakind——ofportableflower-pot，andhegrowsroundit，insteadofoutofit。Hehas，besides，asingularlycomplexnutritiveapparatusandanervoussystem。ButrecollectthedoctrinealreadyenunciatedinthelanguageofVirchow，thatananimal，likeatree，isasumofvitalunities，ofwhichthecellistheultimateelement。Everyhealthycell，whetherinavegetableorananimal，necessarilyperformsitsfunctionproperlysolongasitissuppliedwithitspropermaterialsandstimuli。Acellmay，itistrue，becongenitallydefective，inwhichcasediseaseis，sotospeak，itsnormalstate。Butiforiginallysoundandsubsequentlydiseased，therehascertainlybeensomeexcess，deficiency，orwrongqualityinthematerialsorstimuliappliedtoit。Youremovethisinjuriousinfluenceandsubstituteanormalone；removethebakedcoal-ashes，forinstance，fromtherootsofatree，andreplacethemwithloam；takeawaythesaltmeatfromthepatient’stable，andreplaceitwithfreshmeatandvegetables，andthecellsofthetreeorthemanreturntotheirduty。
Idonotknowthatweeverapplytoaplantanyelementwhichisnotanaturalconstituentofthevegetablestructure，exceptperhapsexternally，fortheaccidentalpurposeofkillingparasites。Thewholeartofcultivationconsistsinlearningtheproperfoodandconditionsofplants，andsupplyingthem。Wegivethemwater，earths，saltsofvariouskindssuchastheyaremadeof，withachancetohelpthemselvestoairandlight。Thefarmerwouldbelaughedatwhoundertooktomanurehisfieldsorhistreeswithasaltofleadorofarsenic。Theseelementsarenotconstituentsofhealthyplants。Thegardenerusesthewasteofthearsenicfurnacestokilltheweedsinhiswalks。
Ifthelawoftheanimalcell，andoftheanimalorganism，whichisbuiltupofsuchcells，islikethatofthevegetable，wemightexpectthatweshouldtreatallmorbidconditionsofanyofthevitalunitiesbelongingtoananimalinthesameway，byincreasing，diminishing，orchangingitsnaturalfoodorstimuli。