886 SUMMABY or CURRENT RESEARCHES RELATING TO 



whicli is edited by Mr. Frank Crisp, with the assistance of several 

 Fellows of the Society, shows that activity in microscopic science is 

 incessant. Last year the Journal included 1008 pages of matter, 

 most of it consisting of summaries giving the essential features of 

 all important papers bearing on microscopical science published 

 throughout the world. This year 756 pages of the Journal have 

 already been issued, and students who use the Microscope are thus 

 better off than the devotees of most other departments of science. It 

 is to be noted as to the Microscope itself, that improvement is not 

 now rapid as regards fundamental principles and their application to 

 the less powerful lenses with which the average student is chiefly 

 concerned, but that considerable advances have been made in the last 

 few years in the theory and practice of the construction of lenses of 

 high powers. Thus under the eye of a skilled observer an excellent 

 objective of 1/10 in. focal length will now accomplish as much as or 

 more than an objective of 1/25 in. not many years ago ; while those 

 now made of the very high power signified by 1/50 in. focal length, 

 and capable of magnifying from 2000 to 10,000 diameters, according 

 to the eye-piece used, greatly surpass in all important qualities lenses 

 of the same power sold by the best makers less than five years ago. 

 Moreover, for some kinds of work the adoption of the principle of 

 immersing the surface of the objective in distilled water or in very 

 pure oil has proved of great value. Thus many delicate points of 

 detailed structure, formerly discoverable only by the most persistent 

 efforts and careful manipulation, can now be demonstrated with 

 comparative readiness. 



It is obvious that if the educative influence of microscopical study 

 is to be very widely diffused, much depends upon the cheapening of 

 good apparatus. This is especially the case if schools are to employ 

 to any considerable extent recent biological methods. Cheap forms 

 of Microscope have hitherto been more or less unsatisfactory. Either 

 they were cumbrous to work, they readily got out of order, they 

 became unsteady, or they did not long continue to magnify clearly or 

 without introducing inopportune colours into the field of view. All 

 the leading makers, however, have recently brought out cheap in- 

 struments of improved construction. Among others, Messrs. Beck, 

 whose name stands high for finish and reliability of workmanship, 

 have recently brought out a so-called ' Star ' Microscope, which 

 combines solidity and steadiness with good magnifying powers (1 in. 

 and 1/4 in. in focal length respectively), suitable for average students 

 and for research within limits. The tube can be inclined at any 

 angle, there is a fine adjustment, the stand is solid and firm, and a 

 diaphragm with apertures of various diameters under the stage can be 

 rotated so as to regulate the admission of light. 



Marked improvements continue to be made in the lantern Micro- 

 scopes used for magnifying objects for public lectures and demonstra- 

 tions. Mr. Lewis Wright has broitght to great perfection a lantern 

 Microscope which throws large-sized and exceedingly clear views of 

 minute objects on to a screen free from distortion or colour. Struc- 

 tures so complex as the minute anatomy of the human tongue, the 



