4«4 



NA TURE 



{March 27, 1890 



seriously mislead the student, but we are more perplexed 

 to discover the reasons which have led in some cases to 

 the separation of the crystalline members of this group 

 from certain of those in the other, and presumably older 

 group, which is defined as consisting of "mica-schists 

 calc-mica-schists, chlorite-schist, &c. To the latter are 

 referred the schists — calcareous, micaceous, and chloritic 

 — near Windisch-Matrei ; to the former the great belts 

 north and south of the Tauern range, which, for instance, 

 occur respectively near Mittersill and Lienz. We cannot 

 understand on what grounds these are distinguished. 

 Further, the great group of schists which sweeps along on 

 the eastern flank of the watershed of the Franco- Italian 

 Alps, as, for example, near the Mont Genevre, has the same 

 colour as those of Windisch-Matrei ; but petrographically 

 they appear to us inseparable from the other group. 

 By some geologists, as is well known, the "lustrous 

 schists " have even been mapped (erroneously no doubt) as 

 altered Trias. 



Still, though we venture to dissent occasionally from 

 Dr. Noe, and think that in all probability a wider 

 personal knowledge of the Alps would have led him 

 occasionally to modify a conclusion and to avoid 

 some slight inconsistencies, we cannot conclude this 

 notice without expressing our sense of the very great 

 value of his work. He has placed a really good general 

 map of the Alps within the reach of all students, for the 

 price at which it is sold is surprisingly low. The map is 

 accompanied by a useful descriptive pamphlet, to which 

 Prof. Suess has written a short preface. 



T. G. BONNEY. 



OLD AGE. 



Old Age. By George Murray Humphry, M.D., F.R.S 

 (Cambridge : Macmillan and Bowes, 1889.) 



IN spite of pessimistic philosophies, man still regards 

 life as worth living, and trusts to attain to a good old 

 age, however miserable his life may seem to impartial 

 critics. This desire, of course, is a necessary condition 

 of human existence, and the destruction of it would entail 

 the extinction of the human race — a contingency, however, 

 which is never likely to arise. Hence, we have no doubt 

 that this volume will be eagerly scanned by innocent 

 persons who are still in hopes of finding some panacea 

 which will enable them to attain the desired length of 

 days. 



But, alas, the number of their somatic cell generations 

 is already fore-ordained in the germ from which they 

 were developed ; and no rule of life can increase this. 

 No man by taking much thought can add a cubit to his 

 stature, nor a decade to the predestined span of his exist- 

 ence. Yet the facts gathered together in this book may 

 afford some hints as to the best way of attaining just 

 this limit. 



On p. 135, et seq., Prof. Humphry reviews the chief 

 characteristics in the mode of life of the favoured subjects 

 of the work. He begins by saying that the results of the 

 collective investigation respecting old age, " have not 

 been such as to evolve anything very novel or startling 

 or to give rise to any fresh theories with regard to 



longevity and the means of attaining it," but only to 

 " show that the maxims and laws which common-sense 

 would dictate hold good, that the real elixir vitce is to 

 be found in the observance of them, and that, as a general 

 rule, those persons live the longest who might be expected 

 to do so." 



The author also emphasizes the fact of the all-import- 

 ance of inherited predisposition among the factors that 

 tend towards producing longevity, and shows that nearly 

 all the subjects of the returns came of a long-lived stock. 

 In most of them, too, the body was well-proportioned 

 and developed, brain development fair, and there was 

 a remarkable absence of degenerative changes in the 

 arteries and cartilages. According to the author, their 

 essential characteristic is that all parts of the body are 

 so well balanced, that the senile decay of function goes on 

 in them all simultaneously, and at an equal rate, so that, 

 e.g., the vascular system is not overloaded and over- 

 worked by a too vigorous digestive apparatus, nor the 

 vessels worn out by an over-excitable nervous and 

 cardiac mechanism, so that if we could induce all our 



organs 



" to arrange 

 This not to be avoided change, 

 So as to change together," 



we should have gone far towards attaining the secret of 

 long life. 



Most of the persons described were temperate, taking 

 little alcohol and meat, and lived active open-air lives. 

 There are one or two startling exceptions to the former 

 rule, however ; such as the centenarian who " drank like 

 a fish all his life," and several others who had always 

 indulged pretty freely in stimulants. 



Another point that Prof. Humphry lays stress on is the 

 fact that most of these people were early risers, and 

 could do with little sleep. It seems that the anabolic 

 processes are more complete and regular when they are 

 accomplished quickly. Apropos of this, he quotes with 

 approval the dictum of the Duke of Wellington : " When 

 one turns in bed, it is time to turn out." 



In discussing the general aspects of his subject, he 

 shows that old age may be said to be a product of 

 civilization, the law of the " weakest to the wall " being 

 altered by the growth of sympathy, and of love for others. 

 But the continued existence of old people among com- 

 munities may (partly, at all events) be accounted for on 

 more utilitarian principles. Weismann remarks : — 



" It [old age] is obviously of use to man, for it enables 

 the old to care for their children, and is also advantageous 

 in enabling the older individuals to participate in human 

 affairs, and to exercise an influence upon the advancement 

 of intellectual powers, and thus to influence indirectly the 

 maintenance of the race." 



Thus we see the production of old age could be 

 counted for simply on the laws of natural selecti^ 

 among nations. 



The fertility of these long-lived individuals is a* 

 above the normal (the average of children born to ea^ 

 whether man or woman, being six), and many of the 

 seem to have borne or begotten children to an advanc 

 age. This, again, is in accordance with the view ad\ 

 cated by the biologist just quoted — viz. that a lengthen!^ 

 of life is connected with the increase in the duration 



