ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
377 
knife is mechanically connected with the winch, whose rotation produces 
on the one hand a see-saw motion of the paraffin block, and on the other 
a pushing of the knife. This is accomplished by means of a slide (e in 
fig. 62 ; K in fig. 63) about 4 by 15 cm., moving in a groove of the cast- 
iron base. This slide lies exactly under the object-holder, and carries 
the knife-holder ss' at one end. At the further edge of the base is the 
micrometer screw J (fig. 63), which by means of a three-armed lever is 
connected with the slider e (K). 
The lever Z is under the base A, and is at one end connected with a 
nut c, which is fastened to the micrometer-screw at d; at the other end 
there is a small slot b, in which a pivot juts out from the knife-slide K. 
The lever is fastened to the base at a by a pin around which it can turn. 
Thus is formed a three-armed lever with its fulcrum at a. When the 
micrometer (endless) screw J is turned the nut c is displaced, a partial 
rotation of the whole lever round a follows, and a corresponding dis- 
placement of the slider K is the result. As the arm a b is shorter than 
a d , the displacements of K are much less than those of the nut c. Thus 
great nicety of working is ensured. 
There is a rackwork for adjusting the movements of the knife, 
whose inclination is regulated by four screws. 
Fig. 64 shows an additional piece of apparatus F, by which the 
smallest paraffin blocks can be arranged for section cutting. The 
arrangement permits the use of those parts of the knife-edge which are 
not generally in play, and thereby affords something like uniform wear 
of the blade. 
Dr. Nowak speaks highly of the precision of the machine, and of the 
ribbon bands of sections. 
Student’s Microtome. — Messrs Reynolds and Branson, of Leeds, 
have made a simple form of microtome, devised by Prof, de Burgh Birch, 
which will be found very useful to students in physiology, botany ,^&c. 
Fig. 65. 
t.The instrument (fig. 65) is arranged to slide on a glass plate; the 
substance to be cut is imbedded, and fixed on the glass plate. Sections 
of any degree of thickness may be cut by raising or lowering the screw, 
and the microtome is arranged so that any razor may be clamped to it. 
Price, with glass plate, without razor .. .. Ss. 9 d. each. 
Ditto, with roughened plate to secure better 
attachment of the imbedded substance .. 4s. „ 
Razors .. Is. and 2s. ,, 
