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SCIENCE. 



THE ADDRESS OF THE PRESIDENT OF THE 

 ROYAL MICROSCOPICAL SOCIETY. 



Lionel S. Beale, F. R. S. 



As it is usual on this occasion for the President to de- 

 liver an address, I venture to offer for your consideration 

 this evening some suggestions in connection with a sub- 

 ject which in one or other of its aspects must needs be 

 of great interest to every one who wishes to learn all he 

 can about the wonderful changes which continually go 

 on in all living things, some being within and some be- 

 yond the present limit of scientific investigation ; and 

 though I shall express some views with which perhaps 

 many here will not agree, I trust my remarks may kindle 

 interest and encourage discussion, rather than offend. 

 Where wrong I shall be glad to be corrected, but I claim 

 permission to speak freely what I think, and liberty to 

 advance my conclusions, which, though not at present 

 very popular, may yet be worthy of your consideration. 



THE MICROSCOPIC LIMIT, AND BEYOND. 



Increased skill and ever-extending knowledge may 

 enable the scientific worker not only to reach the utmost 

 limit of inquiry in his time, but possibly to gratify that 

 constant desire to see into the limitless region which lies 

 beyond the bounds of actual investigation. This is the 

 hope which encourages the thoughtful observer ; for who 

 would not consent to spend years in patient research, if 

 by so doing he could succeed, as it were, in projecting 

 his intellect, were it ever so short a distance, beyond the 

 circumscribed region in which the senses can alone oper- 

 ate? Failures and disappointments may be endured if 

 only the observer's mind be buoyed up by the hope that 

 ere his nerve-tissues grow too old, and begin to fail, the 

 longing of his intellect will probably be gratified. To 

 many, indeed, who are unable or unwilling to look into 

 the secrets of nature, such hopes and desires will seem 

 unintelligible or incredible. They will be regarded as 

 the idle tancies of an idle mind; and the ardent scientific 

 inquirer will be pitied or condemned as a weak, foolish 

 person who, like a child, is unable to repress his morbid 

 curiosity to peer into the unseen, and his craving to kno v 

 the unknowable ; — as one deserving to be classed with 

 simpletons and madmen, on the ground that it is absurd 

 to suppose that a really sensible person would spend his 

 life in hard work without remuneration, in preference to 

 doing that which would enable him to gain wealth, and 

 to live at eise, if not in luxury and enjoyment. And cer- 

 tainly it must be confessed that in few departments of 

 research is there less prospect of gaining by success such 

 rewards as are generally sought for, than in the one to 

 which we are attached. 



The microscopist, like the astronomer, is ever longing 

 to get a little beyond the point at which he has already 

 arrived. Each new fact gained by research seems but to 

 indicate the existence of more and more important things 

 beyond. Limit is reached and then surmounted, but 

 soon a new limit seems to rise from the mists in the dis- 

 tance, towards which the worker is impelled by new 

 hopes and desires. It is this never halting progress 

 which distinguishes scientific from every other kind of 

 inquiry, and particularly microscopical investigation, for 

 it can never be competed. It deals with the illimitable. 

 The boundaries of to-day are found to have vanished to- 

 morrow, and the eyes and understanding begin to pene- 

 trate into regions which but a short time before had been 

 considered far beyond the range of possible investiga- 

 tion. 



He only who was quite ignorant of the many and great 

 improvements constantly being made in our methods of 

 research, and in the instruments required in investigation, 

 would think of fixing any limit to the advance of micros- 

 copical inquiry. Tne records of the work of this Society 

 contain many examples of progress towards and advance 



beyond barriers regarded not very long before, and by 

 considerable authorities, as insurmountable. I well re- 

 member the time when in many branches of inquiry, it 

 might have been truly said that the optical instrument 

 was in advance of the methods of examination ; when 

 our magnifying powers were higher than we could use 

 without losing rather than gaining as regards the defini- 

 tion of delicate structure. As, however, time went on, 

 this was changed. New and improved methods of ex- 

 amining tissues were discovered, and means adopted, by 

 which excessively thin layers could be submitted to ex- 

 amination, and a power of five or six hundred diametres 

 was no longer sufficient to enable the observer to see all 

 that it was almost certain was to be seen. These re- 

 marks more particulary apply to a class of researches 

 upon which I was engaged in 1856-60, concerning the 

 structure and arrangement of the ultimate nerve-fibres in 

 various tissues and organs. Indeed, I feel quite sure that 

 at and before that time advance was actually retarded by 

 the discouragement offered in some quarters, and the hy- 

 pothetical objections raised to the use of very high pow- 

 ers, and more especially to the methods of preparation of 

 the tissues that were necessary before they could with 

 any advantage be submitted to examination. 



Although at this time we can work easily with a twelfth 

 and a twenty-fifth, the results of observation conducted 

 with the aid of such powers are still regarded by some 

 with doubt and incredulity ; and if we draw attention to 

 actual structure and arrangement discovered by the higher 

 powers, which could not possibly be demonstrated with 

 the aid of a more moderate lens, our statements may 

 possibly be met with insinuations that what was advanced 

 as the result of observation was, after all, discovered by 

 the imagination only. 



Our present limit of observation in investigations on the 

 structure and action of the tissues of man and the higher 

 animals, in my opinion, includes the use of magnifying 

 powers of upwards of 2000 diameters. Objects consider- 

 ably less than the hundred-thousandth of an inch in 

 diameter can be studied with success, but how much less 

 i than these dimensions cannot, I think, be determined with 

 accuracy at this time ; for so much depends upon the 

 character of the object, and a number of small points of 

 detail as regards the mode of examination. All who are 

 accustomed to work with high magnifying powers are well 

 aware of the great advantages gained by some very slight 

 change in the degree of illuminating power, the direction 

 and concentration of the rays of light, and very slight and 

 happy alterations in the focus, which may momentarily 

 reveal to the mind new facts of the greatest importance 

 after, perhaps, manyhours of careful but almost profitless 

 study. 



But in other departments of microscopical research, our 

 present means of investigation enable those familiar with 

 j the requisite methods of inquiry to demonstrate character- 

 istics of structure far more intricate and minute than the 

 remarks just made would lead you to infer. Various 

 , modifications in immersion lenses and in immersion media 

 I have greatly contributed to advance our knowledge of 

 I structure and action in the lower forms of life ; and there 

 is every reason to think that, as time goes on, methods of 

 observation will be still improved and new methods dis- 

 covered, and that in consequence conclusions already ar- 

 rived at will have to be greatly modified or entirely 

 changed. Not only so, but by the aid of photography 

 S things dimly seen by the eye may be very distinctly and 

 correctly delineated, and with a perfection of accurate de- 

 tail which a few years ago we should not have supposed 

 to be possible. In all probability, the application of pho- 

 tography to investigations opon minute structural details 

 will be carried far beyond anything yet reached, although 

 it is really wonderful how much has been achieved up to 

 this time 



As regards direct observation, with the aid of very high 

 magnifying powers, upon animai tissues, a department of 



