8O HOW TO WORK 



can easily be cut with a knife to fit the cells intended for the pre- 

 paration. Pins or small pieces of silver wire may be inserted into 

 these slabs, and will adhere firmly although the slabs are very thin. 



Cutting thin Sections of Soft Tissues. 



141. Of obtaining Thin Sections of different Textures for Micro- 

 scopical Examination. The instruments required for obtaining thin 

 sections of soft tissues have been described in pp. 45, 46. See also 

 pis. XIV and XV. 



It is scarcely necessary to observe that such different textures as 

 muscular fibre and gland structures, and other soft tissues, require a 

 process for cutting them different to that which is applicable for 

 cutting thin slices of such tissues as hair, horn, bone, or teeth. 



Where thin sections of no very great extent of tissue are required 

 they may be obtained by scissars, p. 46, by the ordinary scalpel? 

 p. 45, by the double-edged knife, or by Valentin's knife. Whenever 

 a thin section of a thin tissue is made, the instrument employed must 

 be thoroughly wetted with water, and the section, after its removal, 

 should be carefully washed, by agitating it in water, or by directing 

 a stream of water upon it from the wash-bottle, p. 86, fig. 143, 

 pi. XXII. This washing is absolutely necessary to remove from 

 the surface of the section particles of de'bris, which would render the 

 appearances indistinct, and interfere with the clearness of the 

 specimen when it was subjected to examination in the microscope. 

 The section may then be transferred to the fluid in which it is to be 

 examined or preserved. If the specimen be immersed in glycerine, 

 alcohol, or other fluid, the knife must be wetted and the specimen 

 washed with the same. 



148. Cutting Sections and handling Bodies under the Microscope. 

 With practice the observer may carry on a dissection under the 

 microscope. It is not difficult to work under an inch, and under a 

 half inch it is possible to dissect with the aid of a fine knife or very 

 sharp needles. The erector, p. 4, must be employed, or the observer 

 must learn to work although everything appears reversed. Various 

 instruments have been proposed to aid the observer in dissecting or 

 removing specimens which are highly magnified. 



On an instrument for making sections on the stage of the microscope. 



V. Hensen, who has made some beautiful observations on the organ 



of hearing of Crustacea, has designed an ingenious instrument for 



making thin sections of tissues while in the field of the microscope. 



(In Schultze's Archiv, April, 1866, vol. II, p. 46.) 



Under a power of fifty diameters an extremely thin section of tex- 

 tures of a certain hardness may be made with facility. This instru- 



