486 POPULAR SCIENCE MONTHLY 



etc., as great as the vibrational number of the given motion " ; 10 Ohm's 

 analysis of the " periodic motions perceived by the human ear/' 11 and 

 Wheatstone's stereoscope united to demonstrate that the psychical and 

 the physical stand in close connection. 



Finally, Young's color-theory, with its three primary colors — red, 

 green and violet — paved the way for a passage from physical to phys- 

 iological considerations; for it led to the hypothesis of "specific ener- 

 gies " in the nerve-fibers. 



Ere we pass to the epoch-making transformations of last century, 

 two movements, discredited in many ways it is true, yet of importance 

 as preparatory, demand recognition. It may surprise us to find that 

 they are phrenology and physiognomy. Gall and Spurzheim, both 

 physicians, substituted for the descriptive and introspective faculty- 

 psychology an anatomical scheme parallel essentially in result. They 

 concluded that the faculties can be localized in definite portions of the 

 brain, and that these, in turn, can be traced by reference to the surface 

 formation of the skull. Phrenology created wide-spread interest early 

 in the nineteenth century — witness George Combe (1828) in Edin- 

 burgh, who, it may be interesting to relate, received a call to the chair 

 of philosophy in the University of Michigan, or Caldwell and Godman 

 in this country. Through a long series of fluctuating fortunes their 

 suggestions became effective finally as elements in a scientific physi- 

 ological psychology when Broca (1861) located the brain-center of 

 speech; and, ever since, thanks to the labors of Hughlings Jackson, 

 Ferrier, Golz, Hitzig and many others, this has provided an important 

 sphere of study to physiological psychology. 



In similar fashion, the observations, opinions and speculations of 

 Lavatar, in his " Physiognomische Fragmente " (1772), produced a 

 furore; elicited Sir Charles Bell's famous " Essay on the Anatomy of 

 Expression" (180G), with its theory of the relation between intel- 

 lectual power and the facial angle; and, at last, attained complete 

 scientific consecration in Darwin's masterly book, " Expressions of the 

 Emotions in Man and Animals" (1872). 12 Thus positive error and 

 misleading half-truth sometimes serve to state problems which, other- 

 wise, might have failed to gain hearing. One may conclude fairly, 

 then, that questions about the relation of body to mind were in the 

 air throughout the entire course of the eighteenth century and. at its 

 close, had begun to become clamant. 



Ill 



At this juncture philosophical activity assumed unprecedented pro- 

 portions and left a solid deposit destined to a constructive influence 



"Helmholtz, loc. tit., p. 52. 



11 Cf. ibid., pp. 23, 51, 89, 102-3. 



12 Cf. "Physiol. Psych.," Wundt, Vol. II., pp. 598 f. (4th ed.). 



