3«8 



SUMMARY OF CURRENT RESEARCHES RELATING TO 



removable for cleaning. When dissections under water are required, 

 the glass plate is replaced by a glass-bottomed metal tank which fits 

 into a circular opening in the middle of the table. The table is with- 

 out a bottom, so that a piece of white paper may be placed underneath 



Fig. 96. 



Fig. 97. 



for reflecting light up on to the object. The lenses can be taken off 

 and the whole apparatus dismounted and packed within the space of 

 the dissecting table. 



Reichert's Accessory Apparatus for Entomologists. — This appa- 

 ratus (fig. 98) was constructed, on the suggestion of Prof. A. Korlevie of 

 Agrara, for the purpose of fixing small insects intended for observation 

 in such a way that they can be moved and turned in all directions, and 

 be observed with low-power objectives and illuminated by the mirror 

 from all sides. The needle carrying the insect is placed in the cork 

 roller K, which is provided with two ball bearings adjustable by means 

 of the screw F in such a way that the roller is movable in all direc- 

 tions and yet can be fixed in every position. Should the needle be too 

 long for the space under the objective, the substage is removed, and the 

 traverse h is put into its mounting upside down, so that the roller comes 

 under the stage. Then there is space enough for all ordinary objectives. 

 The plane and concave mirror, which is movable in all directions, 

 serves for illumination. The apparatus is intended for affixing to exist- 

 ing stands. 



(4) Photomicrography. 



Photomicrographic Notes.*— Under this title, Mr. Albert Norman 

 gives some very useful practical hints addressed primarily to beginners. 

 He recommends oil-light as the easiest and most certain luminant ; in 

 some cases, such as in photographing very delicate or stained speci- 

 mens, he even considers it the best. He is of opinion that vibration has 

 been greatly over-estimated, and that bad focussing or careless manipu- 

 lation is a more frequent cause of blurs. Table legs should be insulated 

 by felt wads. Sometimes blurring is due to a faulty connection between 

 the fine adjustment of the Microscope and the long focussing rod of the 

 camera. Lime-light is exceedingly useful for high-power work, such as 

 the photography of bacteria at one to four thousand diameters ; but at 

 one thousand diameters it is not essential, for an oil-lamp with an inch 



* Illust. Ann. of Micr., 1900, pp. 110 and 111. 



