1897 THE MICROSCOPE. 1b 
basin. The proposal to aerate the water, which was ad- 
vocated last summer, was fortunately, not entertained. 
Clearing of Vegetable Microscopical Sections. 
By WILLIAM KIRKBY, F. L.S. 
The clearing of vegetable sections prior to staining and 
permanently mounting for microscopical examination is 
a necessary, but frequently a troublesome operation, es- 
pecially if starch be present in any considerable quantity. 
As the process which 1 have followed for over ten years 
has given me such uniformly good results, and as | am 
not aware that the exact procedure has been described 
by anyone else, it seems worth while publishing it in 
order that other microscopists may make trial of it. 
Clearing agents are of two kinds, namely, those which 
act by virtue of their property of strongly refracting 
light, and those which disintegrate and dissolve the ob- 
trusive cell-contents. To the first class belong clove oil, 
cedar-wood oil, cajuput oil, xylol, dammar resin, Canada 
balsam, glycerin, and other similar bodies; to the second 
class solutions of caustic potash, eau de Javelle, eau de 
Labarraque, phenol, chloral hydrate, ete. The useful- 
ness of most of these substances is compartively limited, 
while some of them are decidedly objectionable for per- 
manent mounts because of their energetic action upon 
the tissues. An efficient clearing method should ensure 
the thorough removal of the cell-contents, but should have 
a minimum effect upon the cell-walls. Without discuss- 
ing the merits of each of the usual methods adopted for 
clearing, I may say that-in my handsthe process I use 
more nearly fulfills the above conditions than any other 
I have tried, the sections after treatment being obtained 
in a condition suitable for putting up in liquid, gelatin- 
ous, or resinous mountants. 
Place the sections in a fresh clear solution of chlorin- 
