142 



NATURE 



\yiine 17, 1880 



of constitution, appear to me to depend upon unlike 

 external influences, the inherited constitution itself being 

 dissimilar because the individuals have been at all times 

 exposed to somewhat varying external influences." The 

 present writer has arrived at almost exactly similar con- 

 clusions to these, from a study of the geographical 

 distribution and specific variation of animal forms, as 

 stated in an article on "The Origin of Species and 

 Genera," which appeared in the Nineteenth Century of 

 January last, and it is gratifying to find them supported 

 by the results of a very difierent line of inquiry, and by 

 the authority of so eminent and original an observer as 

 Dr. Weismann. 



The second work referred to in our heading, is Prof. 

 Lankester's British Association evening lecture last year 

 at Sheffield, now republished with illustrations as one of 

 the useful little volumes of the "Nature Series." It 

 discusses the little-known phenomena of "Degenera- 

 tion" as a phase of development much more general, 

 and of far greater importance than is usually supposed. 

 Degeneration causes an organism to become more simple 

 in structure, in adaptation to less varied and less com- 

 plex conditions of life. " Any new set of conditions 

 occurring to an animal which render its food and safety 

 very easily attained, seem to lead as a rule to degenera- 

 tion ; just as an active healthy man sometimes degenerates 

 when he becomes suddenly possessed of a fortune ; or as 

 Rome degenerated when possessed of the riches of the 

 ancient world. The habit of parasitism clearly acts upon 

 animal organisation in this way. Let the parasitic life 

 once be secured, and away go legs, jaws, eyes, and ears ; 

 the active and highly-gifted crab, insect, or annelid may 

 become a mere sac, absorbing nourishment and laying 

 eggs." 



We see incipient cases of degeneration in the loss of 

 limbs of the serpentiform lizards and the pisciform mam- 

 mals ; the loss of eyes in the inhabitants of caverns and 

 in some earth- burrowers ; the loss of wings in the Apteryx 

 and of toes in the horse ; and, still more curious, the loss 

 of the power of feeding themselves in some slave-holding 

 ants. More pronounced cases are those of the barnacles 

 — degenerated Crustacea, and the mites — degenerate spi- 

 ders ; while we reach the cUmax of the process in 

 Ascidians — degenerate vertebrates, and such mere living 

 sacs as the parasitic Sacculina and Lernseocera, which 

 are degenerated crustaceans. Not only such lesser groups 

 as the above, but whole orders may be the result of 

 degeneration. Such are the headless bivalve moUusca 

 known as Lamellibranchs, which are believed to have 

 degenerated from the head-bearing active cuttle-fish 

 type ; while the Polyzoa or Moss-polyps stand in the 

 same relation to the higher Mollusca as do the Ascidians 

 to the higher Vertebrates. 



While discarding the hypothesis that all savages are 

 the descendants of more civilised races, Prof. Lankester 

 yet admits the application of his principle to explain the 

 condition of some of the most barbarous races — " such as 

 the Fuegians,theBushmen,and even the Australians. They 

 exhibit evidence of being descended from ancestors more 

 cultivated than themselves." He even applies it to the higher 

 races in intellectual matters, and asks : " Does the reason of 

 the average man of civilised Europe stand out clearly as an 

 evidence of progress when compared with that of the men 



of bygone ages '> Are all the inventions and figments of 

 human superstition and folly, the self-inflicted torturing 

 of mind, the reiterated substitution of wrong for right, and 

 of falsehood for truth, which disfigure our modern civilisa- 

 tion — are these evidence of progress 1 In such respects 

 we have at least reason to fear that we may be degenerate. 

 It is possible for us — ^just as the Ascidian throws away its 

 tail and its eye and sinks into a quiescent state of in- 

 feriority—to reject the good gift of reason with which 

 every child is born, and to degenerate into a contented 

 life of material enjoyment accompanied by ignorance and 

 superstition." 



This is very suggestive ; but we may, I think, draw a 

 yet higher and deeper teaching from the phenomena of 

 degeneration. We seem to learn from it the absolute 

 necessity of labour and effort, of struggle and difficulty, 

 of discomfort and pain, as the condition of all progress, 

 whether physical or mental, and that the lower the 

 organism the more need there is of these ever-present 

 stimuli, not only to effect "progress, but to avoid retrogres- 

 sion. And if so, does not this afford us the nearest attain- 

 able solution of the great problem of the origin of evil? 

 What we call evil is the essential condition of progress 

 in the lower stages of the development of conscious 

 organisms, and will only cease when the mind has become 

 so thoroughly healthy, so well balanced, and so highly 

 organised, that the happiness derived from mental ac- 

 tivity, moral harmony, and the social affections, will itself 

 be a sufficient stimulus to higher progress and to the 

 attainment of a more perfect life. 



For numerous instructive details connected with de- 

 generated animals we refer our readers to the work itself 

 — truly a small book on a great subject, and one which 

 discusses matters of the deepest interest, alike to the 

 naturalist and the philosopher. 



Alfred R. Wallace 



NATURE'S HYGIENE 

 A'ature's Hygiene : a Series of Essays on Popular Scien- 

 tific Subjects, with Special Reference to the Chemistry 

 and Hygiene of the Eucalyptus and the Pine. By C. T. 

 Kingzett. (London : Bailliere, Tindall, and Cox, 1880.) 



THE subject of this book is, practically. Peroxide of 

 Hydrogen. Such a title as " Peroxide of Hydrogen, 

 with Special Reference to its Sanitary Applications," 

 might not have proved so taking as " Nature's Hygiene," 

 but it would have been quite as descriptive of the 

 subject-matter of the work. Mr. Kingzett strives to 

 show that the position which has been assigned to ozone 

 as ■■Nature's purifier and_disinfectant," is not altogether 

 merited by that body, but that it should rather be given 

 to peroxide of hydrogen. There can be no doubt that 

 these substances have been frequently confounded, and 

 that in numerous instances reactions which have been 

 attributed to ozone have been caused by hydrogen peroxide. 

 It has been stated, for example, that the aromatic parts 

 of flowers produce ozone, and that this substance is 

 formed in considerable quantity by plants rich in essential 

 oils — indeed the late Dr. Daubeny was of opinion that the 

 oxygen evolved from plants by the decomposition of 

 carbon dioxide in sunshine was always more or less 

 ozonised ; and other observers have sought to show that 



