76 TllK AMEKK^AN MON'rilLV [Maivli, 



Skction-Cittinc.. 



Till" tissues ht'inj; rixod, liardcned. jukI imliiHidcd. it is iicccs- 

 s;irv to cut ihcin into tliin sections with a certain area. IMiere are 

 nianx pn)cesses and instruments in* \\ liicli to attain this. . . . We 

 adN ise tlie use <>f Wei.ss's Iiln«;hsh la/or. . . . W hen a «;<)od razor 

 has heen obtained niost caietidlv, keep it awav lioni a manufac- 

 tmer t»r a culler. We make lliis remark \\ lunever we see a ra/or 

 put into tlieii" hands, for on its return it will he exceedinj^ly hril- 

 liaut. but it •L'i/l not cut. Tliis is sinj;ular. hut easily proved by 

 experience. It is as important that the histoloi^ist should know 

 how to sharpen a razor as to know liow to use the microscope. 

 Huv a razor strop and a good stone with a fine u;rain. Pass the 

 razor back and forth over the stone moistened with neat's-foot oil, 

 applvinj; the bhule lijfhtly upon the .stone, and always holding; the 

 eilije t'orwanl (tou jours le tranchant en avant). When well sharp- 

 ened pass it .several times over the leather aiul wash in alcohol to 

 remove the oil. . . . 



Free-Hand Cutting. — This demands a certain manual skill, 

 but it is ol' Ljreat instrumental simplicity, as it recpiires oidy one 

 instrument, the razor. . . . Take a stick of elder pith as larj^e as 

 possil)le anil remove the outer layers, which are lilleil with silica. ' 

 Cut a turrow in it lon<xiludinallv. Gcntlv separate the edi^es of 

 the cleft, and between tiiem place the tissue imbedded in j^um. 

 The elasticity of" the pith will hold the object in the cleft. 'Fake 

 the pith between tiie thumb and finger of the left hand, and the 

 razor in the right hand. Dip the blade in alcohol and while wet 

 lioldlvcnt through the object. ... It is well to support the razor 

 on the thumb nail. The following method by Ranvier for the 

 study of nerves will make the operation easier : The piece, well 

 sponged oH* with bibulous paper, is placed in a little hollow made 

 in the pith. Then pour into the cavity a mixture of pure wax 

 and oil. raised to a temperature not to exceed the melting point. 

 '• When the mixture is cold, the first cut having leveled the surface 

 of the three Ixnlies (pith, wax and oil mixture, object) to make 

 the second, with the razor depress the surface of the pith so as to 

 elevate as small a quantity as possible of the wax and of the ob- 

 ject ; cut by a single stroke made morecertain as the razor rests on 

 a guiding surface. The pith thus u.sed takes the |)lace of a micro- 

 tome." Whatever plan may be adopted the sections float in the 

 alcohol on the blade, and mav l)e ramoved l>y dipping the razor 

 in water. 



Cutting with the Hand (or Ranvier) Microtome. — A long 

 apprenticeship is needed to cut good sections by the foregoing 

 method, and there are a great number of microt(jmes intended to 

 make the procedure entirely mechanical. Ranvier's is the simplest 

 of these. *'It is formed of a hollow cylinder, having at one end 

 a flat plate and at the other a micrometric screw, which raises a 

 piston within the cylinder." To make thin sections by this micro- 

 tome, take rods of elder pith freed from the silicious layer, and 



