ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 



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(3) Cutting-, including- Imbedding' and Microtomes. 



Leitz' Base Sledge Microtome.* — This instrument (figs. 94, 95) 

 consists of a cast iron base provided with a horizontal slide bed, 

 within which moves an accurately fitted heavy sledge which supports 

 the object-carrier. The latter is raised by a micrometer mechanism 

 which is mounted upon the sledge, but which is actuated independently 

 of the motion of the sledge. The knife is supported by two pillars, 

 which can, by means of T-bolts and variously placed slots, be clamped 

 in any desired position, so that the knife may be fixed at right angles 

 for paraffin cutting, or obliquely for celloidin cutting, with respect to 

 the direction or motion of the sledge. When the object is excep- 

 tionally high the knife may be raised by placing below the knife- 



Fig. 94. 



clamps the rings which are usually immediately below the wing nuts at 

 the top of the pillars. The latter may, moreover, be placed as close 

 together as the size of the object will admit, so that small prepara- 

 tions may be cut with a closely supported blade, and therefore under 

 conditions of the greatest stability. Like the fixing of the knife, the 

 bedding and movement of the object-holder insures the utmost degree 

 of rigidity. The advantages resulting from this rigid arrangement for 

 supporting the object are further enhanced by the addition of a new 

 object clamp provided with a universal ball-and-socket joint. This 

 clamp surpasses the usual form of cross-jointed clamps in that the 

 preparation remains in all positions almost strictly at the centre of 

 the clamping device. The micrometer movement is at the back of 

 the sledge, and is operated by the rotation of a knob, which likewise 

 serves to move the sledge to and fro. By suitably adjusting the 



* E. Leitz' Special Catalogue, 1909, 4 pp. (2 figs.). 

 Aug. 18th, 1909 



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