466 PROCEEDINGS OF PHILADELPHIA MEETING. 



ganglion — the cerebrum. In the cerel)ram of the highest part, namely, 

 the external gray matter as sliown by the number and de])th of the con- 

 volutions. Tlien among tlie convolutions an increasing pro})ortion in 

 the highest lobe of the cereljrum — tiie frontal lobe as marked ofi'by the 

 fissure of Roland. I need hardly say tliat the same law prevails also in 

 the evolution of the individual, both pliysical and ps3'^chical. As there 

 is an increasing dominance of mind over body, so in the mind there is 

 an increasing dominance of reflective over the perceptive faculties, and 

 finally of the moral faculties over all. The same is true of social evolu- 

 tion. In all and everywhere Ave find the same law of cephalization. 

 Everywhere — in physical, psychical and social evolution; in education, 

 in intellectual and moral culture, and in civilization — we find an increas- 

 ing dominance of the liigher over the lower and of the highest over all. 

 I do not follow up this thought only because I do not know that Dana 

 himself did so. In a singular degree he united l)oldness of thought with 

 extreme cautiousness in method. 



The third line of thought suggested to his mind l>y his famous voyage 

 was that of volcanism. Early in life, during his Mediterranean voyage, 

 he became interested in this subject, as shown l)y his paper on Vesuvius, 

 the first he ever publislied, but his interest was greatly (piickened and 

 broadened b}' the study of volcanic phenomena in the south seas, 

 esi)ecially in the Hawaiian islands, in accordance with the al)ounding 

 fertility of his thought, he now no longer confined himself to simple local 

 volcanism, but connected this witli all other forms of igneous agency, 

 and especially with those grander movements of the earth crust which 

 determine the greater features of the earth's surface. These movements, 

 tliough so slow and inconspicuous as to be unperceived excei)t by the 

 ever watchful eye of science, yet, extending over.wide areas and acting 

 through inconceivable time, their accumulated efiects far surpass all 

 other forms. Indeed volcanic erui)tions and earthquake sliocks are but 

 occasional accidents in the slow march of these grander movements. 



Thus it is in all things, the really most potent causes are slow in opera- 

 tion and inconsi)icU()Us in their effects and are therefore recognized only • 

 by the scientific thinker. For exam[)le, railroad accidents and steam- 

 boat disasters, plague and pestilence, strike the poi)ular imagination and 

 fill the mind with horror, while the slower but constantly acting effects 

 of dyspepsia and consumption, which destroy their thousands for one 

 carried ofi' by tbe more catastroi)hic way, hardly attract attention enough 

 to enforce their remedy by im})roved sanitary conditions. Similarly 

 wars and revolutions strike the p()i)ular imagination and fill the pages of 

 history, while the slow approaches of political corruption and decay of 



