September. 1910. 



KNOWLEDGE. 



371 



done in the many departments of zoology, and they give one a 

 chance of meeting some of the few who know intimately about 

 the corner in which one's own labours lie. 



The first paper in the general section was by Prof. Y\es 

 Delage of the Sorbonne who discussed " Experimental 

 Parthenogenesis " — one of the most interesting results of 

 modern biology. Delage and Loeb and others, have shown 

 that the unfertilised eggs of sea-urchins, starfishes, and some 

 other types can be made to de\elop parthenogenetically under 

 the influence of a great variety of artificial stimuli. The 

 difficulty is to discover what is the factor common to all the 

 different conditions which take the place of the spermatozoon 

 in this, at least, that they set egg-cleavage agoing — pulling the 

 trigger of development 



\'ery striking also was what followed — a cinematographic 

 exhibition of the development of the egg of the sea-urchin by 

 M. F. Vies and Mile. Chevroton. With remarkable success 

 the films showed the dividing of the egg into two. into four, 

 into eight, and into a rotating ball of cells. The blastula 

 became a gastrula before the eyes of the audience, and 

 the gastrula grew into a pluteus-larva. It was a remark- 

 able achiexement to be able to show — with fine stereoscopic 

 clearness — the whole process ; and it was a great pleasure 

 to see (as one may with a microscope) the quaint plutei 

 rolling about in the water and growing from second to second. 



Dr. Kammerer submitted to the Congress the results of a 

 very interesting series of experiments on the transmission of 

 acquired characters — a question to which he has already 

 made an important experimental contribution concerning 

 Salamanders. Briefly stated, his recent results are as follows. 

 Certain Amphibians, Lizards, Gastropods, and Myriopods 

 take on, wholly or partially, the colour of the substratum on 

 which they live, e.g., yellow earth or black earth. In some 

 cases the progeny showed from the first a colour adaptation 

 similar to that which the parents had acquired, or showed it 

 more strongly than their parents did. Sometimes it was only 



shewn when the progeny were kept in the conditions which 

 aftected the parents. It is a good rule in such cases, however, 

 to wait for the third generation, especially in instances where 

 all that one can say is that the progeny show in the same 

 conditions more than the parents did. They have been 

 longer under the conditions in (juestion, and they naturally 

 acquire more. 



Dr. O. Riddle reported on some experiments on pigeons and 

 fowls as regards the formation of dark pigment (melanin). He 

 regarded them as refuting the current Mendelian hypothesis 

 of colour-development. Wh.at he found was that both the 

 kind and the quantity of melanin pigment produced in the 

 plumage of a bird depend on nutritive and other local and 

 temporary conditions, and not on specific colour-determiners 

 or '■ factors " in the germ-cell. Here again we have the 

 familiar difficulty of balancing the claims of " nature " and 

 '■ nurture." W'hat we must hold firm by is the true platitude 

 that what is expressed in development is the result of their 

 cooperation. 



One of the peculiar features of a number of recent experi- 

 ments on nurtural influence is that there sometimes seems so 

 little connection between the stimulus and its result. Thus 

 Ch. R. Stockard points out that fish-embryos treated with weak 

 alcohol or various anaesthetics tend to develop into one-eyed 

 monsters. 



One of the naturalist's primal impressions, that never seems to 

 lose its wonder, is that of the abundance of life. In journeying 

 to Graz we passed through part of Switzerland — renewing old 

 impressions — and had again to marvel at the wealth of life at 

 high altitudes. Thus at the Col de Balme, between Chamounix 

 and Martigny. at an elevation of seven thousand feet or so. 

 there were not only abundant flowers and butterflies, but 

 plenty of whistling marmots, and several different kinds of 

 birds in some abundance. Conspicuous were the large white- 

 bellied Alpine Swifts, perhaps the most rapid of birds, 

 continually swirling about, all in silence, in the cold air. 



CORRESPONDENCE. 



COMMENTS OX SOME FUNDAMENTAL IDEAS. 

 To the Editors of "' Knowledge." 



Sirs, — Without expecting too much from the analysis of 

 questions under the above title, some irrefutable facts can, 

 nevertheless, be isolated, while the whole may constitute some 

 sort of recreation in reasoning. 



The noteworthy distinction between w'hat may be termed 

 a statical (achieved) Infinite, e.g., Space, and a kinematical 

 (evolving) Infinite, e.g.. Time [connected with the idea of 

 Motion] , seems not uncommonly to be ignored. While, for 

 example, the '' antinomy " (or logical antithesis) joined to the 

 idea of infinite past Time is usually noticed in philosophical 

 treatises, the case of infinite future Time generally remains 

 unconsidered. Nothwithstanding this, any difference in 

 character between the two cases (which might present a 

 pretext for this ignoration in the one instance) appears to be 

 left out of account, and. indeed, the two cases treated as if 

 belonging to exactly the same category or class. 



Let AB represent a straight line prolonged in the direction 

 from A indefinitely. Let AC represent the time achieved at 

 anv given epoch. 



C 

 A 1 B 



The point C (here indicated by a short trans\erse line) 

 moves or slides towards B with uniform \elocity. The 

 line AC, which represents time of finite (definite) measure- 

 ment, elapsed at any date, has two ends, in the particular 

 sense that A and C persistently indicate two boundary points 

 on the line, marking off finite Time accomplished. 



* For (it might be asked), how is a definite length AC to become not definite, by a predicated uniform rate of increase, when we can follow 

 the process ? The length surely must remain definite, however prolonged, or must continue to possess some definite value numerically expressible^ 



t In one respect at any rate, infinite /^ij/ and infinitey'«/w;v time are not properly classable in the same category. In relation to the present 

 moment, /flj/ lime is stationary (statical), whileyw/wre time (augmenting) is kinematical as a concept. Past time, when regarded as an iiifiniiude 

 actually achieved, is (in this phase) more comparable to space than to future time, HO«-achieved. Space, of course, if viewed as 7wn- 

 augmenting, becomes a statical concept, - an infinitude accomplished or achieved. 



So long as the motion of the point C takes place at a uniform 

 rate, and the line AC does not jump out of itself per saltinii 

 (so to speak), it will lengthen uniformly and remain finite 

 between the two points A and C. 



It results that time in the future, actually accomplished, 

 remains finite. Potential (infinite) time in the future, from the 

 very nature of the case, can never become actual, for if an 

 eternity could accomplish itself in the future, the gradual 

 process of addition to time, which we now experience, would 

 cease. Evidently, since the potential infinite remains always 

 on the remote side of the point C, and the actual finite always on 

 the near side of the said point [i.e., between C and AJ , this 

 means that the potential infinite (as such) can never be trans- 

 ferred over, or realised. 



There is no boundary assignable to the conceivabilit\' of 

 gradual addition to the Finite, while the finite character is 

 conserved in continuit}-. There is no barrier to the process 

 of getting greater and greater without becoming inore"' than 

 Finite by the process [a definite numerical value expressible 

 in figures, by the choice of some convenient unit of length.] 



If the straight line AC could undergo some occult variation 

 in the act of lengthening, as some might tend to imply, such 

 an irregularity would destro>' or nullify the process of 

 gradually lengthening, — would imply some catastrophic 

 change in character. And a change in character is excluded 

 while the lengthening process proceeds at a uniforin rate, — 

 which is the predicated characteristic of Time. 



That which we might try to imagine, sometimes called ' the 

 incominensurable ' here, never arrives,— is never achieved. 

 The concept here is a t kinematical concept (involving the 



