154 PREPARATION AND MOUNTING 



the same length of time, so as to soften and render it easy 

 to cut Sections may then be obtained in the manner just 

 described, but they often curl to such a degree from their 

 previous immersion in water as to render pressure necessary 

 to flatten them until dry. They are often mounted dry, 

 and require no care beyond other objects, as in Chapter 

 III. Some, however, are best mounted in balsam, par- 

 ticularly the long sections when used for the polariscope ; 

 these must be soaked in turpentine, and the greatest care 

 taken that all air-bubbles are removed. Others are thought 

 to be most useful when mounted in shallow cells with some of 

 the preservative liquids mentioned in Chapter Y. weak 

 spirit and water, chloride of calcium solution of the strength 

 of one part of the salt to three parts of distilled water, &c. 



The above " section-cutter " may not be within the reach 

 of every student, nor is it absolutely necessary ; though where 

 any great number of specimens is required it iy very useful, 

 and insures greater uniformity in the thickness. Many 

 employ a razor for the purpose, which must always be kept 

 sharp by frequent stropping. Sections of leaves also may 

 be procured by the same means, though, as before mentioned,, 

 they are sometimes divided by stripping the coatings off 

 with the fingers. The cells which come to sight by cutting 

 some of the orchideous plants are most interesting. To cut 

 these leaves they may be laid upon a flat piece of cork, thus 

 exposing the razor to no danger of injury by coming in 

 contact with the support. It may be mentioned here that 

 the razor may also be used in cutting sections of the rush, 

 than which a more beautiful object can scarcely be found 

 when viewed transversely, as it shows the stellate arrange- 

 ments of the parenchyma. This should be mounted dry. 

 In the same way sections of the leaf-stalks of ferns may also 

 be cut, some of which, as Dr. Carpenter states, show the 

 curious ducts very beautifully, especially when cut rather 

 obliquely. 



It has been found a ready method of cutting sections of 

 the rush and such like plants, to suck a solution of gum up 



