ON STUDENT S MICROSCOPES 59 



you can always add to it extra apparatus which you may require, 

 while it is awkward or impossible to send for this from abroad, 

 and much of it is, in fact, not made there, since in the matters 

 of stage management and illumination the English makers are 

 decidedly ahead. Moreover, the student may desire to use his 

 microscope a little for amusement and field natural history as 

 well as for histological work, and then will want apparatus which 

 is of little use in pure histology. Finally, some authorities, 

 as Professor Michael Foster, find the English construction 

 " in every way better and more comfortable to work with ;" 

 but this is, it must be admitted, a matter of taste. On the 

 other hand, the admirers of the foreign microscopes say that, 

 while the optical part, Avhich is the chief matter, is so good, 

 the stand and other parts only need to be adequate to 

 their end. That for those who use a microscope as they use 

 their anatomical scalpels or surgical instruments for pure 

 work, the simplest stand is not only sufiicient but preferable, 

 since the less needless complication you have the better. 

 Also there are persons who, as a matter of taste, find the 

 French construction much more comfortable to Avork with, 

 and the present writer can assert, as a matter of fact, that at 

 least one possessor of two microscopes, a large and stately 

 English instrument, and a small French model, will be found 

 nine times out of ten using the latter. However, as there is 

 one English maker who has constructed a precise reproduc- 

 tion of Hartnack's most popular model, it is possible to judge 

 for one's self. 



9. Accessory apparatus. — The most valuable additions that 

 can be made to a microscope are, first, some contrivance for 

 measuring, and, secondly, some contrivance for drawing. For 

 the first an eye-piece micrometer is the best, but it is rather 

 expensive. For the second, either a camera lucida or some form 

 of reflector, such as Dr. Beale's. Beside these, to aid in illumi- 

 nation, a condensing lens for opaque objects should always be 

 added ; and an achromatic or some other form of condenser 

 for transparent objects in artificial light is certainly an acqui- 

 sition greatly to be desired. Polarizing apparatus and many 

 other pieces of mechanism made by the opticians have a very 

 restricted application in histological work. 



10. One word must be said, in conclusion, on price. We 

 have supposed that a sum of from five to ten pounds is as 

 much as a medical student will be able, and need be called 

 upon, to pay. 



