146 



SUMMARY OF CURRENT RESEARCHES RELATING TO 



1*8, and 2 mm. With such thicknesses if the sections be made 0"015, 

 • 02, • 03, • 04 in thickness, a suitable multiple will always be found. 

 The principle of making the plates consists in rolling out a layer of 

 wax on a sheet of paper, the thickness varying with the size of the model 

 required. Upon the paper has already been drawn the magnified image 

 of the object. Along the sides of the stone are laid two strips of metal ; 

 the surface is then brushed over with turpentine, the paper is placed on, 

 and then the wax having been poured over the paper, the roller is used 

 to make a flat and even layer. 



"When these wax-paper plates are finished, the superfluous parts are 

 cut out, and then they are stuck together so as to produce the magnified 

 model desired. In this last part of course a good deal of manipulative 

 skill is required so that no parts are damaged and that the surface is 

 quite regular. 



Cutting Microscopical Objects for the purpose of Plastic Recon- 

 struction.* — Dr. N. Kastschenko has devised two more modifications of 

 his apparatus intended for being adjusted to the object-holder of micro- 

 tomes, the first of which was described in this Journal, 1887, p. 511. 



The oi'iginal apparatus had for its object to pare down the sides of 

 a paraffin block in such a way that some geometrical pattern might 

 surround the object. This pattern or " definition line " was intended 

 to facilitate the reproduction of the object in a magnified model (plastic 

 reconstruction) from the sections made. 



From the author's point of view of course it is important that the 

 definition or boundary surfaces (which on section of the object are seen 



Fig. 34. 



as definition or boundary lines) should be perfectly parallel, or at any 

 rate have a fixed and determined position. The apparatus which he advo- 

 cates is intended to effect this. The first or original model was intended 

 for the Schanze microtome. The two models given above were constructed 



Zeitschr. f. Wiss. Mikr., v. (1888) pp. 173-81 (2 figs.). 



