i6 



HARD WICKE' S SCIENCE-GOSSIP. 



(i.) Modifications due to the direct result of environ- 

 ment. 



These are believed by many to be never inherited ; 

 and it is a matter of common experience that many 

 of them are not, at all events visibly, in the immediate 

 offspring. Some forms of this sort which have 

 received names are, as the authors of the list say, 

 " mutilated shells which have repaired the injuries 

 sustained from adverse surroundings," and it is 

 perhaps questionable whether such should be named. 

 The double- mouthed condition of Clausilia is a case 

 in point. 



Yet the matter is by no means so simple as at first 

 appears. An ordinary decollated monstrosity comes 

 exactly under the above definition of "mutilated 

 shells which have repaired" etc., against the naming 

 of which the authors of the list so strongly protest ; 

 but on turning to the list itself we find several 

 decollated forms included, two of which were named 

 by Mr. Nelson, one of the authors ! This is well, 

 for we know that decollation, though of the character 

 alluded to in the monstrosities of the list, may become 

 a permanent specific feature, as in Stenogyra decollata. 

 The fact is, that it is extremely difficult to accurately 

 measure the influence of environment as against 

 inherent variability, even in " monstrosities." Thus, 

 the frequency of fracture might well be in part 

 affected by the texture of the shell, which varies, the 

 variations being inherited. Size may be affected by 

 the external cause of want or abundance of food, but 

 there can be little doubt that the power of assimila- 

 tion is also a very important factor, and this is subject 

 to ordinary variability. It is probably selection more 

 than excessive nourishment, that has so increased the 

 size of many cultivated plants and domesticated 

 animals. We see this in the invariable increase of 

 the part selected, instead of a general enlargement of 

 all the parts. 



(2.) Modifications due to inherent variability, and 

 more or less intermittently inherited. 



These are deviations from the average, occurring 

 in the same brood as the normal form, and known as 

 "forms," or "mutations." The vast majority of 

 names excluded from the new list belong to variations 

 of this character, as also do very many retained in it. 

 It is about these that the essential difference of 

 opinion may be said to exist, for I believe that the 

 great majority of conchologists would agree as to the 

 desirability of naming geographical races, which occur 

 independently of the type. 



Albinos, sinistral variations (which, as it seems to 

 me, are quite wrongly called monstrosities), and the 

 ordinary colour and band-variations of Helices, may 

 be classed as mutations ; which, however, under the 

 influence of selection, are ever ready to become racial 

 or specific in character. It is from these mutations 

 that species are made ; they are, so to speak, the 

 raw materials for the making of species. Hyalinia 



crystallina is an albino species ; several species of 

 Pupa and Vertigo are normally sinistral ; and 

 hundreds of other instances might be given, in which 

 the mutation characters of one species are the normal 

 ones of another. To study only the finished article, 

 the well-marked race or species, is I believe a radical 

 mistake ; to learn about the origin of species we must 

 examine the materials out of which species arise. 

 Furthermore, let it not be supposed that the range of 

 a mutation is usually the same as that of the species. 

 A species may have four mutations, A. B. C. D. , 

 and yet very likely the whole four will only be found 

 in a few places (perhaps not anywhere) together ; 

 most localities will produce only A. B. C, or A. D. B. 

 or C. D., and so forth. Helix nemoratis has some 

 hundreds of colour and band-variations, most of which 

 are more or less common, yet probably there are 

 scarcely two counties in England which, if thoroughly 

 explored, would produce the same variations exactly, 

 and perhaps hardly any two parishes would give the 

 same percentage of each. This sounds astonishing, 

 but I believe experienced collectors will agree with 

 me that this is likely to be the case. It has certainly 

 been so in my own experience. 



It is only by the careful study of mutations that we 

 can establish these facts, which are, I believe, of great 

 importance in evolution. Thus, supposing a new form 

 of selection is brought to bear, such as a change of 

 climate, or the introduction of a new enemy, it is 

 easy to see how greatly the power to produce such 

 mutations as can survive will benefit the species, and 

 consequently, since this power is variable, we may 

 have survival in one part, and extinction in another 

 part, of its range. 



( To be cotttimied.) 



SCIENCE-GOSSIP. 



We have received from Mr. F. Row, Braintree, a 

 packet of " Adhesive Corners," invented and regis- 

 tered by himself. The design is an admirable one, 

 especially adapted for use by solicitors, literary men, 

 in public offices, museums, etc. 



Another good man has recently joined the 

 majority. Mr. T. J. Moore, Associate of the 

 Linnean Society, and Corresponding Member of the 

 Zoological Society of London. For forty years he 

 was Curator of the Liverpool Museum ; and it was 

 he who worked it up to its high pitch of zoological 

 excellence. This he did by enlisting the services of 

 all the sea-captains in Liverpool. Mr. Moore also 

 was one of the first curators of museums who 

 delivered popular scientific lectures in illustration of 

 their contents. 



One of our most distinguished practical, as well as 

 theoretical electricians, is Professor Preece, F.R.S., 

 who has been recently appointed chief engineer and 



