372 



NATURE 



[January i8, 19 12 



legs, and as there b no water to cause the gelatinous 

 envelopes to swell up, they remain sticky and adhere 

 to his Icffs. No pads are dcvelojK'd on the forefingers, 

 at any rate in the rare with which the experimi-nts 

 were made. Thus these toads have departed widely 

 from the ancestral habits of the Anura, but Kammen-r 

 discovered that they could be made to return to those 

 habits in a very simple manner by environmental 

 stimuli. 



If the animals are kept at a relatively high tem- 

 perature (25 — 30° C.) they are induced to seek the 

 water in order to cool themselves, and there the 

 processes of ejfg-laying and fertilisation take place. 

 The {gelatinous envelopes of the eggs now swell up 

 and refuse to adhere to the legs of the male, and the 

 spawn is accordingly left to take care of itself in the 

 water. The animals become gradually accustomed, 

 during several breeding periods, to this altered mode 

 of procedure, and will at length behave in the same 

 way even at the normal temperature. At the same 

 time, the number of eggs which they lay increases 

 and the eggs become smaller and poorer in yolk, and 

 therefore more like those of ordinary frogs and toads. 



More important, however, is the fact that the off- 

 spring of these toads are found to be modified in their 

 habits exactly as the parents were. When sexually 

 mature they seek the water, even when kept at the 

 normal temperature, and there unite and deposit their 

 eggs. Still more remarkable is the fact that in the 

 fourth generation of the offspring of these modified 

 toads, kept under the same conditions as the parents, 

 the secondary sexual characters found in frogs and 

 toads which normally lay their eggs in water, and 

 which doubtless occurred also in the ancestors of the 

 obstetric toad, are seen to have reappeared ; pads are 

 present on the forefingers of the male, and the muscu- 

 lature of the forearm is hypertrophied. Here, then, 

 we have a case of atavism or reversion brought about 

 by changed environment, and in which crossing or 

 hybridisation has played no part. The ancestral 

 engrams must be latent in the germ cells, and capable 

 of being called forth by the recurrence of the appro- 

 priate stimuli ; unless, indeed, we suppose that the 

 characters in question have been produced altogether 

 de novo by the changed environmental conditions, 

 which seems highly improbable in so short a time. 



As regards what we may perhaps call the physico- 

 chemical nature of the engrams, Semon adopts a very 

 cautious attitude. Apparently he objects to the idea 

 of material primordia in the germ cells, and purposely 

 avoids molecular interpretations ; but he leaves this 

 question entirely open, except in so far as he regards 

 the engrams as being localised, chiefly, if not exclu- 

 sively, in the nuclei of the germ cells. He also does : 

 not attempt to solve the question as to how the I 

 necessary stimuli reach the germ cells. That they do i 

 reach them, however, appears to be certain from I 

 experimental evidence, and that fact is sufficient as ' 

 a basis for the mnemic theory of heredity. 



The fact that this extremely interesting book has 

 now reached its third edition, having been first pub- 

 lished in 1904, affords a sufficient indication of the 

 interest which is taken in Germany in the views so 

 ably expressed by its author. Artmlr Dendy. 



iNO. 2203, VOL. 88] 



BOV LABOUR AND AFPKENTICESHW. 

 Boy Labour and Apprenticeship. By Reginald A. 

 Bray. Pp. xi + 248. (London: Constable and Co., 

 Ltd., 191 1.) Price 5*. net. 



Ql'ESTlONS relating to industrial administration 

 and regulation are of spi*cial interest in a time 

 of widespread unrest in the working community. A 

 marked improvement in trade has followed a long 

 period of depression. A book on boy labour therefore 

 arrives opportunely. The present production is in- 

 teresting rather as a representation of the points of 

 view of a London County Councillor than as an aid 

 to the solution of the problems connected with the 

 entrv of the adolescent into the working community. 



To deal in a book with these problems it is n«-ces- 

 sary to begin with a clear definition of the problems 

 and to discuss them with direct reference to an actual 

 issue. Mr. Bray recognises this necessity, but he 

 has not escaped from the confusion of ideas which 

 is too common where social problems are the subject, 

 and his proposals for reform are definite only in the 

 form of words in which they are embodied, but are 

 hopelessly too vague to form a basis for any procedure. 

 The confusion begins in the first chapter, on "The 

 Essentials of Apprenticeship." It is stated that an 

 apprenticeship system must satisfy three conditions. 

 First, it must provide for the adequate supervision 

 of the boys until they reach the age of eighteen ; 

 secondly, it must offer full opportunities of training, 

 both general and special — the training of the citizen 

 and the training of the worker; lastly, it must lead 

 forward to some opening in the ranks of adult labour, 

 for which definite preparation has been made, and 

 in which good character may find reasonable prospects 

 of permanent employment. 



These requirements are followed by a general 

 demand that they are to be applied to all boys ; appren- 

 ticeship must be universal. How these essentials are 

 to be assured is admitted to controversy, but that they 

 ought to be assured is taken as axiomatic. Now if 

 these essentials and their universal application to 

 all boys are to be admitted, clearly they must not be 

 specifically associated with preparation for industrial 

 efficiency of workers, but applied to all classes of the 

 community, and in this sense in a general way the 

 propositions will not be disputed as a pious expression 

 of desirable possibilities. 



If suitable supervision can be provided, most people 

 would be the better for it even after the age of 

 eighteen. .'Ml training is good. A job of some kind 

 for everybody is devoutly to be wished. But in pro- 

 ceeding to examine what the author calls the old 

 apprenticeship system, he gets off at a tangent from 

 his definition, forgets that he is dealing only with 

 a very small number of the boys who lived in the time 

 of trade guilds, and that the arrangements which he 

 praises lacked the quality of universality, which lack 

 vitiates the comparison which he proposes between 

 the good old times and the present. 



The summary- of methods of apprenticeship, not in 

 the sense defined in the first chapter, but in the sense 

 of specific contract between employer and employed 

 with mutual obligations, is interesting, but is marred 



