SCIENCE. 



241 



SCIENCE: 



A Weekly Record of Scientific 

 Progress. 



JOHN MICHELS, Editor. 



Published at 

 TRIBUNE BUILDING, NEW YORK. 

 P. O. Box 3838. 



SATURDAY, MAY 28, 1881. 



In his recent address to the Royal Microscopical 

 Society of London, the President, Dr. Lionel S. 

 Beale, F. R. S., introduced some interesting facts re- 

 lating to the present limits of microscopic vision, 

 and indicated the advance that may be anticipated for 

 the future in this direction. 



Within five years it has been often asserted by 

 those who make the Physics of the Microscope their 

 special study, that the limits of microscopic vision had 

 been almost reached by modern objectives, and that 

 further advance was barred by insuperable difficulties. 

 Since this time the record of progress contains numer- 

 ous- instances of advances made beyond these barriers 

 which authorities considered until now insurmount- 

 able. Dr. Beale claims that " he only who is quite 

 ignorant of the many and great improvements made 

 in our methods of research, and in the instruments 

 required for investigation, would think of fixing any 

 limit to the advance of microscopical inquiry." 



With improved instruments, the Microscopists have 

 discovered improved methods of preparing objects for 

 examination, and subtle agents united with the most 

 delicate manipulation are now employed to develop 

 structure, requiring the highest power of microscopic 

 definition and amplification. We remember with Dr. 

 Beale the time (within ten years) when in many 

 branches of inquiry it was truly said that the optical 

 instruments were in advance of the methods of making 

 examinations, when our magnifying powers were higher 

 than we could use, without losing, rather than gain- 

 ing, as regards the definition of delicate structure. 

 All this has now changed; the power of definition of 

 objectives has been more than doubled, but the 

 Biologist, in his investigations, anxiously demands 

 higher powers and more perfectly corrected objec- 

 tives. 



Until recently the Histologist was satisfied with 

 powers of five to six hundred diameters. Dr. Beale, 



in his recent address, states : " Our present limit of 

 obseivation 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 2000 diameters. Objects considerably less than 

 the hundred-thousandth of an inch can be studied 

 with advantage, but how much less than these dimen- 

 sions 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 mode of examination. 



But in other departments of Microscopical research 

 our present means of investigation enable those 

 familiar with the requisite methods of inquiry to de- 

 monstrate characteristics of structure far more intricate 

 and minute than the above remark would infer. 

 Various modifications of immersion lenses and in im- 

 mersion media have greatly contributed to advance 

 our knowledge of 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 discovered." 



Another aid to perfect Microscopy is Photography, 

 for by its use " things dimly seen by the eye may be 

 very distinctly and correctly delineated, and with a 

 perfection of accurate detail which a few years ago 

 we should not have supposed possible." In this direc- 

 tion Dr. Beale states that " in all probability the 

 application of photography to investigations upon 

 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." 



It will thus be seen that a variety of circumstances 

 is steadily leading the way to what may be termed 



A NEW MICROSCOPY. 



Both the Microscope and objectives, as also methods 

 of manipulation, are being revolutionized, producing 

 entirely new results. Even a new style of literature 

 of the subject is developing. As far back as June, 

 1875, the editor of this journal, in a paper prepared 

 for Popular Science Monthly, then foreshadowed this 

 change. The article was headed, " The Microscope 

 and its Misinterpretations." A happy satisfaction 

 then reigned among Microscopists, both with their 

 instruments and their work, and the article was 

 criticised as an assault upon the integrity of Microscopi- 

 cal research. It is some satisfaction to the present 

 writer to find that those who then came forward as cham- 

 pions of the perfect microscopical work of that day, 

 are now the most active leaders of the new reform. 

 We refer to Mr. John Phin, the present editor of 

 The American Journal of Microscopy, who can claim 

 the honor of having established the first successful 

 microscopical journal in the United States, and Pro- 

 fessor J. Edwards Smith, of Cleveland, the author of 



