1888. | BOTANICAL GAZETTE. 9 
washed out of them. Then the roots must be put into alco- 
hol, in order to replace the water they contain by this rea- 
ent. This manipulation, however, must be conducted with 
‘great caution, because the root-tips are very liable to be 
shrivelled. 
I have no doubt that Schulze’s apparatus’ may be used 
here with success, but I found that it is sufficient to bring the 
roots, successively for some hours, or half a day, into alco- 
hol of 20%, 40%, 60%, 80% y5%, and finally into abso- 
lute alcohol. By these means shriveling may be totally 
avoided; whilst the manipulations are very simple, when 
bottles, containing alcohol of the concentrations required, 
are always kept ready and renewed from time to time. 
Now, the alcohol should be replaced by a solvent of par- 
affin, for instance chloroform, benzol or turpentine. These 
first brought into a mixture of absolute alcohul and turpen- 
tine in equal parts, and after some hours into pure turpentine, 
and this again in order to avoid shriveling. After some 
hours the roots may be put into a cold saturated solution of 
paraffin in turpentine. From thence the roots are removed 
into a mixture of equal parts of turpentine and paraffin, kept 
at a constant temperature of from 30 to 40° C, in an ordinary 
drying oven furnished with a gas regulator. After having 
remained an hour in this liquid the temperature 1s raised to 
from 50 to 55°.C, and the roots are finally placed in pure 
melted paraftin, which is renewed one or two times. 
I generally prefer a tolerably firm paraffin, which melts 
at a temperature of about 50° C. When the root-tips have 
remained six or eight hours 1n this condition one may be sure 
I employ a well-known arrangement, consisting of 
metal plate, on which are laid two Gothic-shaped pieces of 
metal, against each other, so as to form a rectangular moul 
for receiving the paraffin, I generally employ these Gothic- 
shaped pieces of two sizes, according to the form of the 
objects to be imbedded. One pair has legs of 1-5 and 4.5, 
4 
*Roots from 
picric acid should t 
*Archiy, fiir mikr. Anat. Bd. 25, p. 542. 
Se leoho) of from 20 to 40 per cent. 
