710 RECORD OF CURRENT RESEARCHES RELATING TO 



firmly by hand, B being merely a clamping-screw to hold the substage 

 apparatus in position, and is but seldom needed, though of great 

 importance under certain conditions. 



Weber-Liel's Ear-Microscope.* — The following is the description 

 given of this instrument in the ' Berlin Microscopical Journal ': — 



To the many and varied adaptations of the Microscope an addition 

 has lately been made, the possibility of which was formerly thought to 

 be extremely doubtful, viz. the inspection of internal parts of the 

 human body which are difficult of access. Although such parts, as the 

 oral cavity and auditory passage, have previously been examined by 

 means of a lens and illuminating mirror, the low magnifying power 

 of the apparatus set narrow limits to the examination. Now, however, 

 the instrument of Dr. Weber-Liel has made it possible, afc least for 

 the ear, to detect the finer abnormalities of structure and in many cases 

 to discover and remove the cause of disease. 



The Microscope, which is shown in Fig. 58, consists of three prin- 

 cipal parts : — 



(1) The Microscope proper. 



(2) The mirror with illuminating lens. 



(3) The pneumatic chamber and flexible tube. 



The body of the Microscope Tj has a conical piece attached to 

 its lower extremity, several of which of different sizes are supplied 

 with each instrument so that one may be screwed on which is adapted 

 for the particular case and will entirely fill up the auditory passage. 

 Above this is a chamber into the side of which an indiarubber tube 

 opens, having a mouth-piece at its other extremity ; this chamber is 

 closed at the upper part by the mirror K which fits air-tight so that 

 when the instrument is introduced into the ear no air has access except 

 through the tube. The Microscope T^ with the eye-piece T slides 

 into the txibe T2, the eye-piece having a micrometer at m. The 

 mirror which closes the pneumatic chamber is inclined at an angle 

 of 45° to the axis of the tube, with its reflecting surface turned 

 towards the illuminating lens G. The reflecting surface has its 

 coating removed in the centre so that a clear view down the axis of 

 the Microscope is obtained through it. The magnifying power of 

 the instrument is about twenty diameters, which is strong enough for 

 viewing the small parts of the ear, as the malleus, stapes, &c. 



Besides the parts above figui*ed and described, there should be also 

 the ordinary speculum and two lenses. One of these lenses, magni- 

 fying about five diameters, is fixed in a short tube and inserted at Tg 

 for making a preliminary examination and (what only could hitherto 

 be done) seeing the position of the parts. The second lens, which 

 magnifies about three diameters, is used in making the operations. To 

 give room for the instruments in the latter case, the cone is rejjlaced 

 by one somewhat longer, which is open at the side; this of coui'se 

 interferes witli the complete shutting-in of the pneumatic chamber, a 

 matter, however, of no consequence as this chamber is not wanted 

 during an operation. 



* 'ZeitbcLr. f. Mikr.,' ii. (1880) p. 175. 



