i88i.] 
299 
Analyses of Boohs . 
no likeness to the physical process of the ether vibrations which 
give rise to it. These ether vibrations are the one and the same, 
though, according to their subjective effects, we call them some- 
times heat and sometimes light. “ The usual classification of 
physical processes into those of sound, light, heat, &c., is irra- 
tional, because in these processes it gives prominence to an 
accidental circumstance, — that is, to the way in which they affeCt 
human beings, who are endowed with various sensations, whilst 
in others, such as magnetic and eledtric processes, it is based on 
quite different marks of classification.” 
The rate at which excitement is transmitted along the sensory 
nerves is not only much slower than is popularly supposed, — 
30 metres per second, — but it varies in different persons, in the 
different senses, and according as the excitement is or is not 
expedted. These measurements, it is suggested, represent the 
crude beginnings of an experimental and physiological psycho- 
logy. To what will they grow ? 
We must pronounce this work an exceedingly useful compen- 
dium. If we have an objection to urge it is that relatively too 
much space has been given to the muscles and to the motor- 
nerves, and too little to those mediating sensation. 
Experimental Researches on the Temperature of the Head. By 
J. S. Lombard, M.D. London : H. K. Lewis. 
It will be known to many of our readers that Dr. Gray, M. 
Broca, and MM. Maragliano and Seppilli had come to the con- 
clusion that the left side of the brain has uniformly a higher 
temperature than the right. Dr. Lombard has carefully re- 
investigated the question, with negative results. He finds, from 
a very prolonged and extensive series of observations, the parti- 
culars of which are here tabulated, that the rises and falls of 
absolute temperature, by which the balance of superiority of 
temperature is shifted from one side to the other, or by which 
equality is brought about, follow no definite law, but are governed 
by agencies liable to constant variation. As the absolute tem- 
perature rises, the average difference between the two sides 
seems to diminish* but the exceptions are so numerous that the 
author lays little weight uoon this generalisation. 
In a second treatise, Dr. Lombard, assisted by Dr. F. H. 
Haynes, examines the effedt of voluntary muscular contractions 
upon the temperature of the head. It appears that Dr. R. W. 
Amidon has recently sought to prove not merely that voluntary 
muscular movement causes a marked rise of temperature at the 
