28 



B. KICFvOfVJILLOTINE. 



This instrument was designed to effect at any desired place, and with a high 

 degree of precision, the hreaking of fine glass objects and instruments such 

 as microneedles or micropipettes. The device consists of a frame made of a strip 

 of brass with a thin groove milled out aloru?: its center and folded to form a 

 square with the groove inside. (Pig. 22). 



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Into this groove are fitted (A) a piece of Gillette safety razor blade, and (B) 

 another piece of blade, cut to form a wedge front and attached to a holder (C), 

 by which it may be drawn back and forth. On top of blade A is a thin piece of 

 cover glass so placed as to have a space between it and the blade just wide 

 enough for the edge of blade B to enter (see Fig. 22, Y) . The edges of this cover 

 glass and blade A, which face blade B, must be accurately lined up, one above 

 the other. The entire frame is soldered to a rod, as indicated. 



In operation, the guillotine is supported by its rod in one of the holders of 

 the micrurgical machine under the microscope and the object, held by the other 

 holder, is introduced between the blades. The guillotine and the object are then 

 approximated to each other until th? object rests against blade A at the place 

 where the break is to be made. Blade B i8 then pushed in gently but firmly 

 against the object and the break is made. If hollow objects, such as micro- 

 pipettes are to be broken, the blades must be scrupulously clean or the pipette 

 may clog. 



If greater delicacy in manipulating blade B is desired, the sliding holder to 

 which it is attached may be changed for a screw, and a hole may be tapped in 

 cross-bar E to receive it. Also, the position of blade B, and blade A with its 

 superposed cover slip, may be exchanged, making the latter the movable, cutting 

 unit. Belkin 1928. 



