November i8, 1897 j 



NATURE 



I 



In the third lecture Dr. Waller sets forth further in- 

 teresting facts relating to the mode of action of carbonic 

 acid gas, and compares it with the effects of repeated 

 stimulation, drawing certain inferences as to the agency 

 of this body in producing fatigue, which it would be out 

 of place to criticise here. 



The fifth and sixth lectures are devoted to the elucida- 

 tion of certain changes in the electromotive properties of 

 living nerve, to which half a century ago du Bois-Reymond 

 applied the term electrotonus. Using the method of ob- 

 serving and recording the responses to periodical auto- 

 matic stimulations already referred to, Dr. Waller de- 

 monstrates du Bois' extrapolar electrotonic currents in 

 such a way as to enable the audience to judge of their 

 correspondence with phenomena of the same kind ob- 

 served in "core models" [i e. cylindrical conductors of 

 which the cores are metallic, the sheaths soaked with 

 solutions of electrolytes), and finally proves, as before, 

 with the aid of ether vapour, that although these pheno- 

 mena resemble those of physical polarisation so closely, 

 they are, notwithstanding, dependent on a vital activity 

 which the nerve loses and recovers again when for a few 

 minutes put to sleep by the anaesthetic. " In the last 

 lecture Dr. Waller goes into the rather more recondite 

 phenomena of " polarisation increment and decrement." 

 His mode of exposition of this subject is so original that 

 one begins to fear that he is about to demolish the inter- 

 pretation of these phenomena which has been given by 

 his distinguished predecessors in this field of investiga- 

 tion. Happily it is not so. When the time comes for 

 explaining, the instructed reader is gratified to find 

 that although the terms employed are peculiar and 

 unusual, there is nothing abnormal about the doctrine. 

 "Active tissue is zincative, resting tissue is zincable.'' 

 Consequently in a living nerve through a certain bit 

 of which a battery current is flowing, the anode is 

 more zincable than the kathode ; for the living sub- 

 stance of the nerve is at rest at the anode, awake at the 

 kathode. But what does zincable mean ? It is a word 

 which Dr. Waller proposes to introduce into scientific 

 terminology because he cannot find an English equi- 

 valent for the German " leistungsfahig." Regarding 

 the " Leistung " of a nerve to be chiefly electrical, 

 its " Leistungsfahigkeit '■' is its " capability of being 

 aroused to electromotive action" (p. 83)— a property 

 which he emphatically distinguishes from "excit- 

 ability," rightly holding that this word ought only to 

 be used to denote the facility with which a response 

 is evoked. 



Dr. Waller's explanation of the increment and de- 

 crement is that the diminished excitability which is the 

 well-known effect of the anode during the flow of a 

 voltaic current along a nerve, is necessarily associated 

 with what he calls increased zincability. Hence if the 

 nerve passes from the electrotonic into the excited state, 

 those parts which are most zincable are most susceptible 

 of excitatory change. The point which is thus enforced 

 — that is, the association of increased capability with 

 diminished promptitude to reaction— is a fundamental 

 one in the physiology of all excitable tissues. There 

 can be no doubt that in relation to the phenomena now 

 in question, it has been brought out in a more striking 

 NO. 1464, VOL. 57] 



way than before by Dr. Waller's excellent forms of 

 experiment, his lucid description, and the admirable 

 diagrams which make those descriptions easy to follow. 



J. B. S. 



NOTES OF A NATURALIST AND 

 ANTIQUARY. 



Memories of the Months; being pages from the Note- 

 book of a Field Naturalist and Antiquary, to wit, Sir 

 Herbert Maxwell, Bart., M.P. Crown 8vo. Pp. xii 

 -f 300. (London : Edward Arnold, 1897.) 



THE competitive exactions of business and social 

 pleasure have their reaction. An increasing 

 number of people are turning with interest to the study 

 of natural history, and are willing to learn from those 

 who can write about it. This is a hopeful sign to those 

 who believe that the social health and physical standard 

 of the nation depend in large measure on affection for 

 country life, and that it would be an evil thing should 

 field and flood cease to afford attractions for active 

 minds. As Sir Herbert Maxwell truly remarks, no head 

 is constructed to carry about an explanation of half the 

 things noticed in the course of a single morning's walk ; 

 but if notes are made at the moment of what attracts the 

 eye, be it a landscape, a ruin, a battle-field, a flower, 

 bird, or insect, recourse may be had at home to the 

 information abundantly stored in books, and the sig- 

 nificance of what seemed commonplace or trivial 

 becomes evident at once. Without attempting to be- 

 come a specialist himself, every one has at command 

 the accumulated fruits of the labours of specialists. 



Acting upon this conviction, it would appear that Sir 

 Herbert Maxwell has long been in the habit of making 

 wayside notes on a variety of subjects, and from time to 

 time has amplified and published them for the benefit of 

 others. 



His method of presenting them to the reader is not 

 very new, as will be perceived by those who are 

 acquainted with the Rev. Robert Willmott's "Summer 

 Time in the Country," Mr. Oswald Crawfurd's " Round 

 the Calendar in Portugal," Prof Miall's "Round the 

 Year," and other books of a similar nature ; and it might, 

 perhaps, have been better to have arranged his mis,- 

 cellaneous and fragmentary notes under zoological, 

 botanical, and antiquarian headings, instead of grouping 

 them, as he has done, under the headings of the months 

 to which more often than not they have no particular 

 relation. This plan would have been more convenient 

 to specialists as affording them the opportunity of at 

 once finding all that relates to their own subject, instead 

 of having to search for scattered notes through three 

 hundred pages. 



No one, however, who dips into this little volume will 

 begrudge the time bestowed upon it, for whether he be 

 in search of particular information on a given subject or 

 not, he will perforce linger upon many a page wherein 

 he will find both amusement and instruction. 



What more amusing, for example, than the author's 

 account (pp. 259-266), of the attempts made to decipher 

 the inscription on the celebrated Ruthwell Cross, 

 variously interpreted— and by experts too— as Runic 



