THE THOMA MICROTOME 



465 



be shifted vertically and horizontally by means of the small screw a, 

 and is fastened by means of the milled head, m. By the pinion n it 

 may be displaced over 90, and as great an inclination can be taken 

 in a plane perpendicular to this by the supporting metal frames by 

 means of the pinion p. In this way every desired inclination of the 

 object to the knife can be readily secured. 



Fig. 393 presents the same object-holder, but instead of the 

 cvlinder a simple pair of jaws with the screw m to secure objects of 

 every variety. A cylinder-holder as in fig. 393 can be placed in 

 these jaws from which the benefits of the Neapolitan holder can be 

 secured. But fig. 396 shows a still greater improvement which can be 

 applied to both object-holders, v&.ja perpendicular displacement by 

 means of a coy and pinion governing the height of the mass from 

 which the sections are to be cut. 



The elevator in fig. 393 is supported on one side by the prism P, 

 ; i nd on the other by the rod C; these are joined by the bridged, 



= cf 



FIG. 394. Object-holder movable about two horizontal axes at right angles 

 to each other. 



to which a cogged bar is fastened, into which a pinion catches, which 

 is moved by the lever Y, allowing a perpendicular displacement of the 

 object of 12 mm. At O is the millimetre scale on which the perpen- 

 dicular displacement can be read off by means of the index x. 



An object-holder movable about two horizontal axes situated 

 perpendicularly to each other is seen in fig. 394. These positions 

 are fixed by the milled heads & 1 , b ; e shows the jaws for holding the 

 object, into which, however, cylinders like fig. 396 may be intro- 

 duced. This object-holder has a perpendicular displacement con- 

 trolled by a screw. The part. K, which supports the chief axis of the 

 j;i\vs, is fitted on to the triangular prism Si, the lower part of which is 

 furnished with hinges ; on the hinge the screw V moves, which at its 

 upper end lies close to K, and is sustained in this position by the 

 steel plate gr, so that K is carried up and down with it, and this 

 movement is read off by a scale under S. 



H II 



