April 9, 1885] 



NA TURE 



529 



would have no doubt incited his just indignation if it had been 

 performed by his friend " Sludge," of spiritualistic celebrity. 



I cannot help remarking on the coolness of Prof. Lankester's 

 assertion, that my views are " undeniably based upon a mistaken 

 interpretation of defective preparations." Prof. Lankester 

 evidently thinks his opinion final — but he is bold to say it is 

 "undeniable." 



My sections have been seen and approved of by a great 

 number of competent histologists and zoologists, and, although 

 some of them are not so pretty as those prepared by the paraffin 

 method which Prof. Lankester extols, they certainly show a great 

 deal more. The paraffin method is well known to me, and I have 

 examined a great number of slides prepared by it. I have pos- 

 sessed a series of sections so made in the Cambridge laboratory 

 by an excellent histologist, and have rejected them as worthless: 

 they show nothing but the connective tissue framework. Nerve 

 fibres and nerve end organs are alike destroyed. 



The whole question of the effect of reagents on the tissues is 

 a wide one. The paraffin process destroys much which remains 

 in the cocoa butter process, first devised by Prof. Schiifer. I 

 esteem this process far superior to that now used in the laboratory 

 at Cambridge, and by Prof. Lankester and his assistants. 1 

 should not fear to place my specimens side by side with Prof. 

 Lankester's before an unbiassed histologist ; and I am content 

 to wait the decision of future observers upon my work. New 

 views are met with little favour by those who are committed to 

 old ones, and, whether I am right or wrong, I expect no justice 

 f r om a critic who shows such determined bias as Prof. Lankester. 

 Benjamin T. Louse 



If Prof. Lankester imagines that he has any complaint to 

 make against the Council of the Linnean Society for having 

 published Mr. Lowne's paper, I must decline to consider the 

 subject with him in your columns. He is himself a Fellow of 

 the Society, and the anniversary meeting of the Society is due 

 next month. If he then thinks it wise to ask any questions upon 

 the subject, I shall be in my place and most happy to answer 

 them. George J. Romanes, 



Zool. Sec. L. S. 



How Thought presents itself among the Phenomena 

 of Nature 



In your issue of the 12th inst. the Duke of Argyll asks, " Is 

 there any difference in this respect between molar and molecular 

 motion ?" namely, as regards the persuasion which most men 

 entertain that where there is motion there must be some " thing " 

 to move. The answer to this question appears to be the very 

 direct one that there is the following fundamental difference between 

 molar motions and some molecular motions, and that it intimately 

 concerns that belief. All molar motions arc secondary motions, 

 i.e. they consist in the drifting from place to place of underlying 

 motions (and, indeed, in the case of those motions which human 

 beings can perceive even with the utmost aid of the microscope, 

 they consist in the drifting from place to place of vast accumu- 

 lations of such underlying motions), while, in contrast to this, 

 there are some molecular motions which arc primary — i.e. which 

 have no other motions underlying them, and which do not consit 

 in the drifting from place to place of more subtile motions. 



His Grace correctly expresses the common opinion in the 

 following words — that "an atom 1 is only conceivable as an ulti- 

 mate particle of matter." Now the term "particle of matter" 

 in this statement needs to be scrutinised. As commonly under- 

 stood, it means something minute which we should be able to feel 

 or see or perceive by some of our senses were it not for the blunt- 

 ness of those senses ; and this, as science shows, means that 

 The Duke of Argyll here employs the word "atom " in its etymological 

 sense ; and it is scarcely necessary to point o'.it that the term when so used 

 different thing from any of the sixty-seven complex bodies known 

 as chemical atoms, which have intricate internal mod ns as 

 [ to us by the spectroscope, and of which the molecules of compound 

 bodies are known to be made up. The chemical "atom" could not under 

 - an ultimate particle of matter. 

 tand the I Hike of Argyll to propose these words as a description 

 (not of anything the existence of which has been ascertained by experimental 

 science, but) of that substance, matter, or thing the conception of which he 

 and most other men believe to be the inseparable concomitant" of the con- 

 ception of motion, but for the existence of which in external nature no other 

 evidence is forthcoming than this supposed law of human minds. 



Now, even if the supposed law were a law from which we could not free 

 ourselves, it might reasonably be maintained that it proves nothing about 

 external existence; but in truth it is not a law, but only a widely prevalent 

 habit of mind, as is demonstrated by the fact that the study of nature has 

 extricated some minds from it. 



certain specific motions are present, viz. motions of those par- 

 ticular kinds which are competent, indirectly and through a long 

 chain of intermediate steps, to finally occasion visual, tactual, 

 or some other sensation in our minds. The statement, accord- 

 ingly, as commonly understood, really amounts to this — that no 

 motion can be present unless certain underlying motions are 

 also present ! 



But to the uninstructed apprehension the statement has 

 quite a different meaning, a much fuller one, and one which lies 

 outside the domain of motion. Before they have made very 

 careful investigation, men do not know that there is no green 

 colour in grass or hardness in a rock. They are unaware that 

 what is really going on in the grass is not a state of g eenness, 

 but vast myriads of motions, 1 each of which is repeated about as 

 often every second as there are seconds in thirty millions of years, 

 which motions in the grass occasion undulatory motions around 

 of a like rapidity, some of which occur within our eyes, and, 

 acting upon some compound or compounds in the black pig- 

 ment which lies behind the retina, produce there an effect 

 (probably a fugitive photographic effect consisting in some 

 chemical change of one or more of three compounds in the 

 pigment). This change, whatever it is, excites the optic nerve 

 to make a stir within the brain, and it is this last motion (which 

 we may safely say is utterly unlike the external phenomenon, 

 though uniformly resulting from it through the steps enumerated 

 above), which is what determines the perception of green in our 

 minds. Similarly, when the vast accumulation of molecular 

 motions which is called my finger approaches that other accu- 

 mulation of motions which is called a rock, these motions act on 

 each other, and my finger is compressed upon certain nerves, 

 exciting them to produce those motions within my brain which, 

 though quite unlike the motions outside, are the motions that 

 are really accompanied by the sensation of hardness. But by 

 uninstructed minds the colour of the grass and the hardness of 

 the rock are confidently believed to be external phenomena, and 

 not even phenomena of motion at all, but absolutely stationary 

 phenomena in external Nature. 



Finally, we must never forget that beliefs in the human mind, 

 whether they be pure or mixed up with errors, can neither control 

 nor even exercise any influence whatever upon what is really 

 taking place in external Nature, which is the object of our inves- 

 tigation. What is really going on in Nature is to be ascertained, 

 so far as it can be ascertained at all, not by projecting human 

 beliefs into external existence, but by applying whatever modicum 

 of dry light we can win from the slow but gradually encroaching 

 progress of scientific discovery. And the necessity for this 

 caution is intensified where we find, as in the present instance, 

 that the belief has resulted from the way our brains and the 

 brains of our ancestors have grown, under the influence of an 

 experience of motion which has been so one-sided that it has never 

 extended to primary motions at all, nor even to any but very 

 coarse forms of secondary motion, omitting, along with many 

 others, all those motions, whether primary or secondary, that 

 occasion most of our sense-perceptions ; and all this, combined 

 with suppositions about other phenomena in which these pheno- 

 mena have been quite misunderstood. Scientific scrutiny, so 

 far as it has penetrated, finds motion throughout external 

 Nature — motions everywhere, motions underlying every pheno- 

 menon, however different from motions some of them may seem 

 to common apprehension ; and no scientific investigation has as yet 

 detected anything but motions. This is the positive side of the 

 inquiry ; and its negative side is that it would be manifestly 

 illegitimate to draw an inference about what really exists outside 

 us from t lie habits of thought which have been engendered in 

 most human minds by a narrow and one-sided experience mixed 

 up uiih palpable errors. We, therefore, arc not in a position to 

 'tat we know of anything existing in t/te outer world but 

 matrons and relations between motions. 



The abstract of my Royal Institution discourse, which you 

 were so good as to publish, only attempted to give a bare state- 

 ment of the successive steps of the argument with which it deals, 

 and I fear it is too condensed for clearness ; but, as I am myself 

 persuaded that the argument is sound, I hope that your corre- 

 spondent will find that a fuller account of it which I am preparing 

 will put all its essential parts in a sufficiently distinct light. 

 Dublin, March 20 G. Johnstone Stoney 



1 The relations which the parts of motion can hav a to one another or to 

 other motions are all numerical or space and time lelations. Motions may 

 be numerous, feu. simultaneous, successive, straight, curved, flat, tortuous, 

 swift, slow, periodic, continuous, linear, or pervading a volume ; but they 

 cannot be green motions or hard motions. 



