872 



SUMMABT OF CURRENT RESEARCHES RELATING TO 



projecting ends of the tin-foil are connected with the wires of a 

 battery. 



For researches on blood-corpuscles EoUett * used a modification 

 of this apparatus made by bringing the strips of tin-foil nearly to 

 meet in the centre. The blood-corpuscles were placed between them 

 and spread out so as to touch the margins. 



DippeVs I (fig. 201) was devised to obviate the inconveniences of 

 Harting's, attendant upon its length, and upon the fact that the 

 connection with the battery wires is very loose, and that the bent 

 wires are liable to be easily disturbed by the hands. 



It consists of a not too thin glass plate ah c d, ot the same size as 

 the stage, on each side of which is fixed a small coil of covered 

 copper wire (m and n), the wire being wound on glass tubes. The 

 inner end of this wire is (to obtain greater facility of movement) bent 

 at right angles in a horizontal plane, and the end either hammered 



Fig. 201. 



^@ilIIM! 



-L' 





//AAy/A'/-mm/^/^/y',/\ 



flat or soldered to a piece of platinum so as to allow it to lie easily 

 under a cover-glass, and not to raise the latter so much that high 

 powers cannot be used. In order to prevent the ends of the wires 

 from shifting, and to enable them to be adjusted to the object, they 

 are carried under two small strips of glass so that they cannot be 

 easily moved. The free ends of the wires are attached to a holder 

 which also receives the wore from the battery, both wires being fixed 

 by screws. 



The apparatus can either be held on the stage of the Microscope 

 by the stage clamps, in which case it will be more or less movable, or 

 it can be dropped into a brass frame having two pins beneath fitting 

 into the holes for the spring clamps. 



Schafer's % (figs. 202-4) does not differ essentially from some 

 of those already described. The glass slide (fig. 202) has two strips 



* SB. K. Akad. Wiss. Wien, 1. (1865) p. 178. 



t Dippel, op. cit., pp. 659-60 (1 fig.)- 



X Schafer, E. A., ' A Course of Practical Histology,' 1877, pp. 37-9 (2 figs.). 



