344 



NA TURE 



[February i 2, 190^ 



the boundary conditions can be obtained by the aid of the 

 1\ ol L. A. ; and if the application of this principle leads to 

 results which are dynamically unsound or impossible, the 

 original hypothesis is vitiated even though the formula; to 

 which it leads should be found to agree with experiment. 

 To endeavour to explain some new phenomenon by intro- 

 ducing a hypothetical term into the energy function, and to 

 deduce the equations of motion and the boundary conditions 

 by means of the P. of L. A., is perfectly legitimate as a 

 tentative process ; but the results thereby obtained require 

 careful examination in order to ascertain whether or not 

 they violate any of the fundamental principles of dynamics. 



In some theories on the action of magnetism on light, the 

 Hypothetical term introduced into the energy function gives 

 rise to certain additional terms in the equations, by means 

 of which the motion and forces are specified, which make 

 some of the forces discontinuous at the surface of separation 

 of two different media. Theories of this kind consequently 

 violate Newton's third law of motion, and can at best be 

 only regarded as stop-gaps until some better theory has been 

 discovered. On the other hand, the introduction of hypo- 

 thetical terms into the equations which determine the forces, 

 or some of them, may lead to an energy function which fails 

 to reproduce the original expressions for the forces when 

 the P. of L. A. is applied ; and in cases of this kind the 

 principle affords a valuable test of the correctness of the 

 previous work. The principle, like a great many other 

 mathematical theorems, has its uses, but to convert it into 

 a " graven image " is to court disaster. A. B. Basset. 



Fledborough Hall, Holyport, Berks, January 30. 



The Horny Membrane of Neohelia porcellana. 



Two years ago, Miss Edith Pratt published in vol. v. of 

 Willey's " Zoological Results " a paper on the anatomy 

 of Neohelia porcellana. In this paper attention was direi ted 

 to a horny membrane lining the hollow tube which forms 

 the axis of the colony, and the suggestion was made that 

 this horny membrane is secreted by the Neohelia itself. The 

 single specimen which Miss Pratt had to investigate was, 

 unfortunately, a small one, and in the criticisms which 

 appeared some doubts were expressed as to whether this 

 horny membrane was not secreted by some tubicolous worm 

 which formerly inhabited the hollow tube of the corallum, 

 and not by the Neohelia itself. I have recently had the 

 opportunity of examining specimens ©f two species of the 

 closely related genus Amphihelia, one (.1. oculata) from a 

 depth of 240 fathoms off the coast of Florida, the other 

 {A. ramea) obtained by H.M.S. Porcupine in the Faeroe 

 Channel, 363 fathoms. In both of them there is a horny 

 membrane similar in character and position to that described 

 for Neohelia. Now it is difficult to believe that a worm 

 forming the same kind of tube, with the same habit oi 

 mysteriously disappearing when the corals are preserved, 

 occurs in such widely separated districts as Florida, deep 

 water, New Britain, shallow water, and the Faeroe Channel, 

 deep water. The only reasonable conclusion is that these 

 madrepores do actually secrete this horny membrane them- 

 selves. Sydney J. Hickson. 



Owens College, Manchester, February 2. 



Genius and the Struggle for Existence. 



Mr. Bulman, in Nature of January 22, urges that what 

 is good for the individual or race will survive unaided. But 

 surely this is contrary to well-known facts. Man, with the 

 increase of specialisation, which (whether it be an unmixed 

 good or no) we find associated with his advance to a greatei 

 mastery over the rest of Nature, has become, so to speak, 

 a polymorphic species, like the ants, bees or termites ; and 

 while in all species we find more or less mutual aid, in 

 polymorphic species it is especially obvious that it is not the 

 isolated individual types, but the total combination that 

 natural selection regards, since the isolated types may be 

 quite incapable of reproducing their kind and performing 

 their special duties unaided. 



In all sui li 1 ases, the " survival " of the individual types, 



and of the community as a whole, depends, not on the com- 

 petence of individuals to survive unaided, but on the re- 

 cognition, instinctive or conscious, of each other's value, 

 and the resulting mutual aid, given either under instinct 

 or in conscious exchange. Now, as I understand, Sir O. 

 Lodge has simply pleaded that steps be taken which, while 

 (pace Mr. Bulman) not interfering one whit with the educa- 

 tion of the 9999, shall lead to the recognition of the one 

 exceptional genius, with a view to mutual aid, i.e. so that 

 he may be set free to do the work of pioneer and leader, 

 which he alone can do; and early, because ars longa. vita 

 brevis. 



We know that genius can be reared in night-schools, and 

 about Palissy the potter ; but ought we to count on our 

 potter burning his furniture for our good, if we, with plenty 

 of ordinary fuel, deny it him? 



In the essay to which he refers in his letter in Nature 

 of January 29, Dr. Wallace attaches less importance to the 

 rearing of a few men of exceptional qualities than to the 

 weeding out of the worst and raising the average ; but 

 surely, without giving undue and exclusive credit for 

 advance to the pioneers and prophets, we may take it that 

 men like Darwin and Wallace himself, to mention only one 

 type, will, under natural selection, render the later more 

 conscious steps of man's evolution easier. 



Dr. Wallace, in the letter referred to, speaks of the 

 " fittest " not surviving under existing civilisation, mean- 

 ing that many of the specialised types, which form important 

 elements in our polymorphic communities, are not fittest to 

 survive, and continue to reproduce their kind in more 

 primitive or more ideal communities. But this, of course, 

 accords well with the principle of the " .survival " of those 

 types " fittest " to the actual environment. (Survival, of 

 course, does not postulate direct reproduction any more 

 than it postulates long life; the "worker" bees "sur- 

 vive.") Further, Dr. Wallace's hopeful attitude shows 

 that he really trusts " natural selection " to steer the best 

 races of man to a point whence their further, more self- 

 conscious, progress (still, as always, under natural selec- 

 tion) will be more and more in accord with Nature's will, 

 and so less wasteful and pain-fraught. 



Man is a self-conscious part of Nature, with the power to 

 " look before and after "; and doubtless the races of man, 

 which will rise highest under natural selection, will not let 

 their faculty of taking counsel from natural and human 

 history rest idle ; but, just as Dr. Wallace himself showed 

 years ago that " sexual selection," in the sense of choice of 

 mates, had no power at all against " natural selection 

 (such selection being, I would say, of a faculty or instinct de- 

 veloped by natural selection, and from time to time modified 

 by natural selection to suit changes in the environment), 

 so this conscious " human selection " is but a faculty of 

 man that is being developed (indirectly, perhaps) by natural 

 selection, and can have no power at all to thwart " natural 

 selection," though its wise use may save our race much of 

 the pain that results front fruitlessly " kicking against the 

 pricks." G. W. Butler. 



February 3. 



It is, of course, true that genius has no survival-value in 

 the struggle for existence between individuals or against 

 physical conditions. But the case is very different when 

 we come to the struggle between groups — tribes, village 

 communities or nations. A tribe which produces a fine 

 bard has far more fighting power than a tribe which has 

 no singer. The possession of a noble literature makes 

 England far more formidable than she otherwise would be. 

 And from the days of Hint instruments until now, the in- 

 ventor has been the salvation of his people. 



F. W. Headley. 



Remarkable Meteorological Phenomena in Australia 



On Wednesday, November 13, 1902, we experienced here in 

 Australia some most extraordinary meteorological phenomena. 

 For the previous five or six days, exceedingly hot, dry weather 

 had prevailed, owing to winds blowing from the Australian 

 interior, where a huge anticyclone was resting, in a coaslward 



NO. 1737, v OL. 67] 



