954 RECORD OF CURRENT RESEARCHES RELATING TO 



attached to the stand ; a short bit of tube slides into the end nearest 

 the stage, and may be drawn out till it nearly touches the slide ; to 

 the other end is attached a rubber tube c with a mouthpiece. When 

 the object on the end of the hair is brought directly over where 

 i\ is desired to bo placed on the cover, the tube is carefully racked 

 down till the object nearly touches the cover ; now, by gently breathing 

 through the tube, a film of moisture will form on the cover, in the 

 most beautiful manner if the tube be pointed right at its lower end, 

 and will, if we stop breathing, again quickly disappear. Suppose 

 now, we flood the cover with moisture, and depress the tube, the hair 

 touching it, the object will be at once taken oif, and by a little manipu- 

 lation not easily described, but easily performed, and mainly consisting 

 in so placing the hair by revolving the ring that its point, slipping 

 forward on the glass, as the tube is depressed, will push the object 

 here or there, into lines or circles, without danger of its flying ofi', or 

 being again picked up, if we keep the cover moistened by gently 

 breathing. It is astonishing how gentle a breath will flood the cover 

 with moisture, and one must be very careful not to blow through the 

 tube before the object is dislodged, or it will inevitably be blown away. 

 When the moisture evaporates, as it will at once, the gelatine will 

 hold all fast, and then there is no need of any heating of the cover, 

 which might do harm by possibly charring the gelatine, only one must 

 be sure it is really dry before placing it on the little drop of balsam 

 on the slide. The bulb h catches the condensed moisture, and must 

 be emptied occasionally. 



Apparatus for Focussing Dissecting Microscopes.* — Herr Hil- 

 gendorf, of Berlin, suggests an arrangement to be worked by the leg 

 for focussing dissecting Microscopes. These, as is known, strain the 

 eyes, owing mainly to the necessity of using both hands in the dis- 

 secting process, which makes the constant adjustment of the focus 

 irksome. 



The inventor's apparatus (which can be at once applied to any 

 instrument without the help of a mechanic) consists of a rather strong 

 brass wire, 1^ mm. diameter, which at one end is hooked to the knee, 

 and at the other is twisted round a cork, the latter being hollowed out 

 in the middle, so that it can be pressed firmly over the adjusting 

 screw of the Microscope. The wire should be bent at right angles 

 5 cm. from the screw; and then, by the raising or lowering of the leg, 

 or side motion of the knee, it can be moved in the desired direction, 

 and the focus varied. The flexibility and elasticity of the wire ofter 

 peculiar advantages, and do away with any complicated mechanism 

 of levers and screws. 



Improved Mounting for Camerse Lucidse. f — Professor L. Me- 

 lassez suggests an imj^rovement to the mounting of the camerje 

 lucidii3 of Milne-Edwards, Nachet, and others. 



These are fixed to the Microscope by means of a ring which 

 encircles the tube, and on which they are jointed. The oj^ticians 



* '8B. (Jcscll. Naturf. Freumle, Berlin,' 187S, p. 187. 



t ' Tmvaux Liiborat. Histu). Coll. France,' 1877-S (187S)) p. 117. 



