260 Mr. J. J. Woodward on the Modern 
study the detailed observations upon which it is based without 
feeling how meagre and unsatisfactory the evidence relied 
upon really is. It is, at best, only sufficient to indicate the 
importance of further inquiry, and to suggest the necessity of 
avoiding certain obvious errors of method which complicate 
and obscure the results of the investigations hitherto made. 
The opinion that mental effort is accompanied by an in- 
crease in the temperature of the brain was first propounded 
by Lombard in 1867. Using a delicate thermo-electric 
apparatus of his own contrivance, he observed during mental 
effort a rise of the surface temperature of the head, which 
sometimes amounted to as much as one-twentieth of a degree 
centigrade*. Subsequent and more elaborate investigations 
confirmed him in this conclusion, which has also been supported 
by observations made with thermo-piles by Schiff and Bert, as 
well as by the use of surface thermometers in the hands of Broca 
and L. C. Gray of Brooklynt. Gray claimed to have observed 
a maximum rise of as much as two and a half degrees Fahren- 
heit. These physicians and some others have also investigated 
the relative temperature of the two sides of the head, of diffe- 
rent regions on each side, the variations produced in certain 
regions by voluntary muscular movements, and those resulting 
from localized brain-diseases f. 
T'o attempt any discussion of these interesting studies and 
their conflicting results would lead me altogether beyond my 
prescribed limits. It is enough for my present purpose to 
* J.S. Lombard, “ Experiments on the Relation of Heat to Mental 
Work,” The New York Medical Journal, vol. v. 1867, p. 199. 
+ J.S. Lombard, “ Experimental Researches on the Tdinpardeits of the 
Head,” Proc. of the Royal Society of London, vol. xxvii. 1878, p. 166; 
Idem, “The Regional Temperature of the Head,” London, 1879; Idem, 
“ Experimental Researches on the Temperature of the Head,” London, 
1881. Moritz Schiff, “ Recherches sur l’échauffement des nerfs et les 
centres nerveux & la suite des irritations sensorielles et sensibles,” 
Achives de Physiol. norm. et path. t. iii. 1870, p. 5 et sey. Bert, Com- 
munication to the Société de Biologie, read Jan. 18, 1879, in ‘ Gazette 
Hebdomadaire,’ Jan. 24, 1879, p. 63. Broca, Communication to the 
French Association for the Advancement of the Sciences, at the Havre 
meeting of 1877, in Gaz. Hebd., Sept. 7, 1877, p. 577; also Gaz. Méd. de 
Paris, 1877, p. 457 ; Idem, in London Med. Record, Jan. 15, 1880. L.C. 
Gray, “Cerebral Thermometry,” The New York Med. Journ. vol. xxviii. 
1878, p. 31; also ‘Chicago Journ. of Nervous and Mental Diseases,’ 
yol. vi. 1879, p. 65. 
t See, besides the papers cited in the last note, C. K. Mills, in the 
New York Med. Record, vol. xiv. 1878, p. 477, and vol. xvi. 1879, p. 130; 
Maragliano and Seppelli, ‘ Studies on Cerebral Thermometry in the In- 
sane,” translated by J. Workman, ‘The Alienist and Neurologist,’ St. 
Louis, Jan. 1880, p. 44 et seg.; R. W. Amidon, “ The Effect of willed 
Muscular Movements on the Temperature of the Head,” ‘ Archives of 
Medicine,’ April 1880, p. 117. 
