112 



SUMMARY OF CURRENT RESEARCHES RELATING TO 



FiG. 3. 



with the illuminator and to where the pins stand, the whole cap can be 

 taken off for the purpose of putting glass in should one be broken. 



For dry lenses I place the flame lower than the opening and use no 

 condenser, but open the shutters to their fullest extent. You will obtain 

 different results by using the light at longer and shorter distances. For 

 examining blood-corpuscles, latter should be mounted on cover-glass, 

 and you can get the best results by using less light." 



Czapski's Ear- (Tjrmpanum) Microscope.* — At the instigation of 

 Prof. Kessel, the representative of aural surgery in the Jena University, 



Dr. S. Czapski undertook the construction of 

 a Microscope which, provided with its own 

 means of illumination, should by its handy 

 form permit of observation of the ear under 

 a magnification of about six to eight times. 

 The following arrangement was given to the 

 instrument (fig. 3) which repeated trials 

 proved to be the most suitable. 



An objective of about 10 mm. opening and 

 20 mm. focal length is connected by a tube 

 60 mm. long with an eye-piece magnifying 

 ten times. The objective alone contributes 

 nothing to the magnification ; it simply 

 throws the image in approximately un- 

 changed magnitude in front of the eye-piece, 

 so that the whole magnification is about that 

 of the latter. Above the eye-piece is screwed 

 a tube 25 mm. long, which carries a dia- 

 phragm for directing the line of sight, here 

 so widely divergent, but this is not absolutely 

 necessary. The length of the whole Micro- 

 scope is about 100 mm. 



Above the objective is a reflecting prism 

 (silvered on the hypothenuse surface) which 

 covers half the objective, and for the avoid- 

 ance of all external reflections is completely 

 inclosed with a tin cover. TLe position of 

 the prism is adjustable, so as to direct the 

 light exactly in the middle of the field of 

 view. The light from a small electric in- 

 candescent lamp, after passing through a 

 lens, is thrown upon the prism through an 

 opening in the tube opposite the prism. 

 Lamp and illuminating lens are contained 

 in a side tube, the former being indepen- 

 dently movable and easily replaceable. Instead of the glow-lamp a gas 

 or petroleum lamp can be used, placed at the side. A socket in which 

 the Microscope slides smoothly is attached by means of a bayonet catch 

 to the ordinary ear-funnel ; for the passage of the side tube the socket 

 is slit along three-quarters of its length. The above mode of con- 

 nection of funnel and tube was preferred to a solid join, partly in order 



* Zeitschr. f. Wiss. Mikr., v. (1888) pp. 325-7 (1 fig.)- 



