i HAITI: i; VIM. 



the paraffin which may happen if it IK- allowed to 



an( ] to gel as homogeneous a mass as possible 



Unitive imbedding has been done in a watch- 



.:,! it on the top of cold water until all the paraffin 



; . :m d then h-r it sink to the bottom. When 



,,], rll , oul blocks containing the objects. If 



has been smeared with a drop of a mixture 



- of glycerine and water before putting the 



..Hi,, int.. it, the solidified paraffin will generally detach 



If in a single cake and float up in a few minutes, or 



l,,,urs at any pate. DC not attempt to remove it entire 



by \\arming tin- bottom of the watch-glass. Similarly with 



tin- paper trays or metal imbedding boxes. Or you may 



put them to eool nil a cold slab of metal or stone. 



-, K \ cools tlif ma l.y passing a stream of cool water through 



tit.- itnlMMldin- tube d.-rrilx-d above ( 137). MAYER cools the mass in 



tli.- [.uratlin-ti-lit in. mid- ( l:',7i l.y passing <.<>ld water through a special 



rable \\.itT-liath. \\liirh allows of the arrangement of the objects by 



tr.m-mitt-d liirlit imdrr a dissecting microscope, see M itth. Zool. Stut. 



ipel,vr,I8 ;.. IJ 1 .' : liif'-i-n. Mbnafoscftr. Ja. IKstf., iv, 1887, p. 39. 



L complicated apparatus for the same purpose is described by MEISSNER 



/ . .V //.-.. \\iii. I'.'oj. p. ^86). Similarly, HAHN, ibid., xxv, 1908, 



p. M. and K LPPEB8, /////.. xxiv. l\H)7 . p. % J51. 



The parallin blocks with the objects are now mounted on 



the carrier of (lie microtome in position for cutting, and 



paivd to tin- propel- shape (next ). If any bubbles or 



or opaque spots be present, prick with a heated 



'll (> till all is smooth and homogeneous. The same should 



'l"iie if any cavities present themselves in the course of 



cntt ii I n bad cases, re-imbed. 



1 14. Shape and Orientation of the Block of Mass to be cut.- 



lill'er accordingly as the cutting is done with a slanting 



quare-sel knite (see next ). In the first case, 



besl trimmed to a three-sided prism, and 



rotated as in Fig. 1, so that the knife enters it at the 



i' :>l >hc angle c. When the section is 



adhere to the knite only by the angle c, and can 



readily be remove. 1 by means of a brush or needle. 



''I 1 rl 'tself >li..iil<l com,, to lie in tlie block close to the 



tli; " l! '" knife al first cuts only paraffin, and 



