1895.] MICROSCOPICAL JOURNAL 217 



of a hollow cylinder, and not parts of a perfect plane ; besides, 

 the rocking or vibrating arm admits of only a very limited 

 movement, so that the instrument is suitable only for cutting 

 sections of objects of very limited dimensions ; nor is the posi- 

 tion of the block adjustable. Moreover in none of the auto- 

 matic microtomes now in use it is possible to place the knife at 

 right angles or any other desired angle to the direction in 

 which the block to be cut is moved — a great desideratum in 

 botanical or other work in which an inclined knife is necessary. 

 In order to supply an instrument serviceable especially to 

 teachers, as well as to all classes of students, botanists, pa- 

 thologists^ histologists and zoologists, the designer has at- 

 tempted to bring together all the desirable features of pre- 

 viously invented instruments in as simple, convenient and 

 compact a form as possible, without sacrificing rapidity and 

 efficiency of action. 



The working parts are an oscillating lever, which is pro- 

 vided with a clamp at one end into which the paraffine- 

 holders are adjusted, and at the other with a simple handle. 

 This lever rests upon trunnions on either side, and these in 

 turn rest in triangular notches at the top of the two pillars, 

 between which the lever oscillates. At the cutting end of 

 the lever a spring pulls the lever down and effects the 

 sectioning and also the adjustment for the next section. The 

 lever is pushed over and adjusted for the successive sections 

 by a hollow screw, through which passes the trunnion on 

 the side away from the knife. This screw is fixed to a 

 toothed wheel, three inches in diameter, which revolves 

 close by the side of the oscillating lever. The toothed 

 wheel and screw, actuated by a pawl fixed to the side of 

 the lever near the handle. The number of teeth which this 

 pawl can pass in a single vibration, downward is controlled by 

 a fixed stop screwed into the under side of the oscillating lever 

 near the handle; the end of this stop striking on the top of the 

 bed-plate thus brings the lever to rest at a constant point in its 

 downward excursion. An adjustable sector by the side of the 

 toothed wheel throws the pawl out of gear after a given radius 

 of the wheel has been turned through an arc embracing the 6e- 

 sired number of teeth. This adjustment is also effected before 



