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XII. — On a Neiv Microtome. 

 By C, Hilton Golding-Bird. 



{Read li th May, 1884.) 



The necessity for providing some instrument which offered the 

 advantages ot modern microtomes and yet was within the reach of 

 those whose work being of intermittent character did not warrant 

 their employing the somewhat elaborate instruments that are 

 found in laboratories, made me originate the instrument shown in 

 figs. 83 and 84. 



The microtome is intended to be held in the hand during use, 

 and is of two forms — one for ice and salt, the other for ether. 

 The former (fig. 83) consists of a cylindrical vulcanite chamber 

 closed at the bottom by a brass screw-lid, and at the top by a 



Fig. 83. 



Fig. 84. 



disk of vulcanite, having in the centre a plate of brass (freezing 

 plate) 7/8 in. in diameter, and terminating in the chamber by 

 a rod of brass. A metal cap surmounted by a glass plate and 

 pierced in the centre to allow the freezing plate to project, screws 

 over the upper end of the cylinder, the outer surface of which 

 bears a male screw of hard metal on which the cap turns. As the 

 cap is turned round a spring catch clicks at given intervals ; these 

 are so arranged that as the cap rotates from left to right each 

 click shows that it has sunk on to the cylinder 1/1000 in. ; hence 

 any tissue fixed on the freezing plate projects, at each click, 

 1/1000 in. through the hole in the glass pla-te of the cap, and a 



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