1915] The Ottawa Naturalist. 175 



BOOK NOTICE. 



Nerves— By Professor D. Fraser Harris, M.D., D.Sc, F.R.S.E., 



Etc., Professor of Physiology, Dalhousie University, 



Halifax, N. S. 



This most admirable handbook on "Nerves " belongs to that 

 excellent series, "The Home University Library of Modern 

 Knowledge," published by Williams and Norgate, London. 

 The series ranges over such diverse fields as Literature, Art, 

 History, Philosophy and Science, and the authors include some 

 of the most eminent specialists of our time. Professor Fraser 

 Harris's little treatise of nearly 2 50 pages will rank among the 

 best, for it is brightly written, full of interesting matter, thor- 

 oughly up to date, and as clear and concise as could be desired. 

 The book has a distinct literary flavour, as might be expected 

 from a writer who has the distinction of being a member of the 

 exclusive "Authors Club" of London. 



Nobody, in these days of stress and strain, needs to be told 

 that he possesses nerves. Most people are only too painfully 

 aware of the fact, and like James David Forbes, the Scottish 

 physicist, compelled to confess "I am laid on my back, and 

 unable to revolve through the smallest aliquot parts of a right 

 angle without a tremendous twitch." 



A clearer description of the nerves, and of nerve functions, 

 than Dr. Fraser Harris gives in his first two chapters cannot, 

 we feel sure, be found, though a few good figures of the brain, 

 spinal cord, and of actual preparations, not diagrammatic, would 

 have been helpful to ordinary readers. Many curious facts 

 are detailed in the earlier chapters, stich as the ascertained 

 speed of nerve impulses, viz.: 180 feet per second in man's 

 motor nerves. These nerve impulses are not the same as 

 electrical waves, though all neural activity, as of all muscular 

 activity, is accompanied by electrical disturbances. The con- 

 tinuity of the neuraxone is carefully explained and in Chap. Ill 

 the nature of nerve centres, or specialized groups of nerve cells, 

 are admirably elucidated. The nerve centres are a "hierarchy," 

 the lower centres obey the higher, says the author, there is no 

 equality, but there is co-operation, surely an object-lesson for 

 some politicians' Curiously enough nerve activities are not 

 specific for experiment shows that a nerve for inhibiting the 

 heart was grafted on to the nerve for dilating the pupil of the 

 eye, and on being stimulated the heart-nerve actually dilated 

 the pupil (p. 78). The character of nerve activity depends upon 

 the tissue or organ in which the nerve ends. Habit or the form- 

 ing of nerve-paths, individual susceptibility or the truth that 

 " what is one man's meat is another's poison," and other interest- 



