1892.] THE MICKOSCOPE. 131 



for a smaller stage than the length of the slide, so that this, pro- 

 jecting, admits of the slide being grasped and swung around the 

 optical axis. These advantages, however, are not generally ap- 

 preciated, and even if so, are offset by the drawback that in mov- 

 ing the slide it is apt to be tilted. 



Spring clips are usually of similar construction, although vary- 

 ing in detail and curves. Properly constructed clips should have 

 such thickness of metal and be so bent as to allow specimens to 

 be brought under them without resistance and keep them properly 

 in place without too much pressure and consequent friction. 



A o-lass stas^e and slide-carrier mav be considered a srood in- 

 vestment, as it admits of ths convenient manipulation of the slide 

 without the grating feeling which usually accompanies the direct 

 movement of the slide on the stage. Where systematic examina- 

 tions of a specimen are to be made, a mechanical stage will be 

 found a great convenience, and in petrographical work it is almost 

 a necessity. 



A sub-stage may, in a general way, be said to be preferable 

 when it is adjustable, particularly in the use of a condenser. It 

 is absolutely necessary to adjust the condenser for different ob- 

 jectives, and this must be done so nicely that a sliding movement 

 is hardly sufficient. In biological work the condenser is at the 

 present day a necessity, and this is now constructed as a separate 

 attachment with all the necessary adjustments, in which the rack 

 and pinion is deemed of first importance. 



\_To be contiiiued.'\ 



Microscopy and the General Practitioner. 



By WM. N. BEGGS, M. D. 



SAINT LOUIS, MO. 



Instructor of Histology, and Director of the Histological Laboratory, St. Louis Medical College. 

 \^From the Medical Fortnig-htly.'] 



If questioned, almost every physician will acknowledge that 

 he ought to have a microscope, and be able to use it. Further- 

 more, almost every physician will more or less reluctantly confess 

 that he himself does not possess one. The reasons for this are 

 not very hard to discover. They are comprised under the fol- 

 lowing heads : the lack of proper microscopical instruction at the 

 colleges at which they have studied ; the failure to properly ap- 

 preciate the scope and advantages of microscopy as applied to 

 general practice ; the want of time to put into practice knowledge 

 previouslv attained ; and, finally, a mistaken idea that a suitable 

 microscopical outfit must necessarily entail a great expense. 



