1895] MICROSCOPICAL JOURNAL 219 



with a movable side and screw for clamping objects, so that 

 rather tough stems may be firmly held between blocks of cork, 

 while the more delicate vegetable tissues, or such as must be 

 embedded in fresh carrot, soaked in gum and hardened in alco- 

 hol, may also be firmly held for sectioning by the same device, 

 provided the pieces of carrot are first trimmed into the right 

 shape. The same style of holder is equall}'- applicable for hold- 

 ing the corks — if properly trimmed — upon which tissues are 

 embedded in celloidin or in gum. This style of holder also 

 enables one to embed very long objects entire in parafiine — 

 such as earth-worms — and to cut them as a single piece, pro- 

 vided the surrounding paraffine is carefulh'- trimmed so as to 

 have two opposite sides parallel. An object six inches long and 

 three-quarters of an inch in diameter embedded in this way 

 may be cut into an absolute continuous series of sections with- 

 out losing any essential portions. This h accomplished by 

 slipping the block through the quadrangular clamp for the dis- 

 tance of half an inch every time a half-inch of the object has 

 been cut off in the form of sections. One-half inch is the 

 length of block which can be cut atone time without re-adjust- 

 ing the feed-screw which moves the block and vibrating lever 

 over toward the knife, the whole being kept firmly in place 

 against the face of the hollow screw b}'- a strong spring which 

 presses against the end of the trunnion on the outside of the 

 iron pillar on that side of the instrument where the knife is 

 fastened, so that all the sections are of exacty the same thick- 

 ness from first to last. Cutting up large objects in the manner 

 above described is not possible with any other form of micro- 

 tome yet constructed. 



Almost any section knife — wide or narrow-bladed — will fit 

 into and be firmly held by the knife-clamp, which is, however, 

 intended more especially to hold an ordinary razor. The best 

 razors for cutting sections have been found to be those of the 

 best make only, such as Wade & Butcher, or Joseph l-odgers 

 & Sons, of Sheffield. Only such razors as hold an edge well 

 should be used. 



For ribbon cutting by the paraffine method, the block con- 

 taining the object, after it is trimmed and soldered to the paraf- 

 fine with which the holder is filled, by means of a heated wire. 



