482 SUMMARY OF CURRENT RESEARCHES RELATING TO 



It appears to us regrettable that so many opticians should struggle 

 to issue " studonts' " Microscopes, the chief aim of which appears to be a 

 low cost of production regardless of tho modern requirements in such in- 

 struments. Our own experience is that with a stand well equipped with 

 substago appliances for controlling the illumination, every good objec- 

 tive may bo made to yield images at least 50 per cent, better than are 

 possible without such appliances. A " student " should obviously com- 

 mence his training in microscopy by learning to use his optical battery 

 in the most effective manner, which practically necessitates his being 

 provided with a stand altogether superior in construction to those usually 

 supplied as " students' " Microscopes. 



Since tho above was written the writer of the article on which we 

 were commenting replied * to a similar criticism as follows : — - 



" Another eminent professor, for whose opinion we have great 

 respect, in reply to our argument in favour of the Acme No. 5, urging 

 the inexpensive construction combined with thorough efficiency, of the 

 fine-adjustment, presents the well-known theoretical objection to this 

 form, and (while willing to admit that he might not be able to tell, by 

 looking through the Microscope, which side of the stage was most ele- 

 vated) says that in his experience expense is not an objection if the 

 Microscopes are likely to be effective and durable in use in the labora- 

 tory. He considers it desirable to pay more and get instruments free 

 from theoretical objection. He speaks of his experience in Germany 

 with German laboratory Microscopes ; how each year they required to 

 be sent to the maker for repair. Eight here is a strong argument in 

 favour of the construction of the fine-adjustment adopted in the Acme 

 No. 5. In instruments of the usual German type the operation of the 

 ' slip-tube ' brings a great strain on the slide of the fine-adjustment ; in 

 the Microscope above referred to the two adjustments are entirely 

 separate, and there is no strain on the fine-adjustment from the use of 

 the other ; in fact, there is no slide or joint whatever that can wear 

 loose. The slip-tube adjustment is carried upon a solid arm, to which 

 it is firmly dovetailed and screwed fast. We are willing to admit that 

 another form of fine-adjustment may be preferable for the expert en- 

 gaged in work which requires the use of substage condenser, highest 

 powers, &c. ; but for the ordinary work of the histological laboratory 

 we believe that it will prove eminently adapted. In the language of 

 modern science, its structure being suited to the conditions of its 

 ' environment,' it will survive, being of the ' fittest.' " 



"American Microscopes— A Complaint." — A great sensation has 

 been caused in the United States by the publication | of the following 

 article by Prof. C. S. Minot, condemnatory of American Microscopes. 

 The author's criticism is much too sweeping and indiscriminate. 



" Every autumn when the colleges and medical schools of the country 

 begin their Academic years, there are many students who come to their 

 instructors seeking advice in regard to the purchase of Microscopes. 

 Often they appear already furnished with an instrument of which they 

 are anxious to learn that the lenses are particularly good. 



" As it has been my duty for several years to conduct a large class 

 in practical histology, I have had frequent applications for advice 

 about Microscopes, and have seen and examined a great many different 



* Queen's Micr. Bulletin, v. (1888) p. 2. t Science, x. (1887) pp. 275-6. 



