The Louse. An account of the lice which infest man, their medical importance and control

Abstract

The war of 1914-18 called forth in all countries an immense output of research on the louse-its biology and the best means of combating it under war conditions. The 20 years which followed, although they have added much to our knowledge of the louse-borne diseases, have added almost nothing to the efficacy of existing methods of louse control. With the renewed outbreak of war the louse will again become a military problem-how important a problem will depend upon which of the louse-borne diseases make their appearance among the troops. Already the evacuation of children from the large towns has brought a realization of how widespread is infestation with head-lice among the civil population of this country. It is singularly fortunate therefore that just at this moment Professor P. A. Buxton has been able to produce a monograph on the louse, which brings together all the scattered information on this subject which everyone who has to deal with lice will wish to know. The author states in his preface that this work formed part of a book on medical entomology which is in preparation, but it has been adapted to form a complete book in itself. The author accepts the view that the head-louse and body-louse are closely related physiological races of a single species, Pediculus humanus. For most purposes they may therefore be considered as one. Their external and internal anatomy and their physiology are described. Their biology is considered in two sections dealing with individual biology and collective biology. The former consists in the relation of the physiology of the louse to its reactions in its environment and to the range of conditions under which it is capable of existence. The collective biology is the study of populations of lice and the fluctuations to which these are subject. It is in this field that Professor Buxton has himself contributed most in recent years and it is particularly valuable to have a lucid summary of his conclusions to date. The relation of lice to relapsing fever, typhus and trench fever is fully described and the value of this part of the book is much increased by an up-to-date account of the development of the Rickettsias and Spirochaetes in the louse, and short comparative descriptions of murine typhus and the tick-borne relapsing fevers. The chapter on control contains both a systematic account of the insecticidal methods applicable to the louse and a discussion of the practical measures for utilizing these methods in different circumstances. Many gaps in our knowledge on all these matters are pointed out. A chapter on the crab louse, Phthirus, and an appendix on the technique of rearing lice for experimental purposes conclude the book. The volume is nicely illustrated with drawings by Mr. H. S. Leeson. It is crammed with facts set out in a readable form and is destined to become the vade-mecum of everyone who is called upon to deal with lice from whatever point of view. V. B. Wigglesworth.