162 THE NORTHERN MICROSCOPIST. 
NOTES ON THE PREPARATION AND STAINING 
OF WOOD SECTIONS. 
By M. H. StiLes, PHARMACEUTICAL CHEMIST. 
| en following notes on the above subject are abstracted from a 
paper read before the Doncaster Microscopical Society, April 
2oth, 1881. 
Stems of all kinds should, if possible, be cut when fresh. If 
they cannot be obtained in this state, they may, previous to cutting, 
be soaked in cold or tepid water, or in a mixture of equal volumes 
of spirit of wine, glycerine, and water (as I have recommended in 
a previous paper on the subject).* Fresh stems or roots can be 
preserved in this medium for almost any length of time, and will 
remain in excellent condition for the section machine. In cutting 
sections I make use of an arrangement (devised five or six years 
ago) by which the blade of the razor is kept from contact with the 
glass plate of the machine by two small screw clamps which I term 
razor guards, (Fig 29.) These slide on the blade, one being fixed 
at each end, and are kept in position by a small screw at the upper 
side of each. The clamps are about three-eighths of an inch wide, 
and are made of sheet brass one-twenty-fourth of an inch thick. 
They ensure a smoother and more steady motion than when the 
whole of the blade is in contact with the plate, and the edge of the 
razor is preserved in much better condition, as it touches nothing 
but the substance to be cut. These guards were made for me by 
Mr. Hy. Crouch. Sections require bleaching before being stained. 
The bleaching solution, “made by mixing one-fourth oz. of chloride 
of lime with a pint of water, shaking occasionally for an hour, and, 
after allowing the sediment to subside, decanting the clear solu- 
tion.” The process of bleaching should be carefully watched and 
stopped when complete. Tissues vary so much in colour and 
density that no fixed time can be given for bleaching them. Very 
thorough washing is necessary. ‘The elimination of the chlorine 
* Monthly Microscopical Journal, March, 1876. 
