516 



SUMMARY OF CURRENT RESEARCHES RELATING TO 



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



Broek's Simple Microtome for Serial Sections.* — A. J. P. v. d. 

 Broek, as the result of several years' experience, highly recommends the 

 following instrument as being simple in construction and easy in 

 manipulation. Fig. 135 shows the microtome as seen from the left and 

 slightly from the front, fig. 186 is a longitudinal section, and fig. 137 is 

 a horizontal section through a b in fig. 186. The instrument stands on a 

 heavy cast-iron base which can be clamped down by a position-screw, 3. 

 The trapezium-shaped slide, 4, is supported by two side pieces, 5, and a 

 bar, 7, connects the slide with a crank, 6, whose movement imparts to 



Fig. 135. 



the slide the necessary backward and forward motion, and presses the 

 object-holder against the knife. If the object is imbedded in paraffin, 

 the paraffin is melted on to a brass plate, 26, which can be screwed on 

 and off ; a celloidin preparation is fixed with a clamp (fig. 185). The 

 hemisphere, 22, is hollow, and can by a special arrangement be fixed in 

 any desired position, so as to give any suitable inclination to the pre- 

 paration ; this effect being attained by a circular plate, 24, to whose 

 lower side is attached a perforated rod. Through the perforation passes 

 a kind of crank connected with the screw, 25, whose movement (see 

 fig. 136) gives any desired inclination to the hemisphere. The sleeve, 9, 

 containing the mechanism of the object-holder, rests on a micrometer- 

 screw, 10, and is gripped on both sides by the rims, 8, of the frame. 

 The micrometer-screw rests with its lower point on screw 13 and its 

 upper end is fixed by the rod 14 ; the whole micrometer-screw is there- 



* Zeitschr. wiss. Mikrosk., xxiv. (1907) pp. 268-74 (3 figs.). 



