552 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
borne in mind. These are, that the preparation while standing dehy- 
dration in strong spirit is distorted when transferred to the turpentine ; 
for such preparations, though properly fixed and hardened, will not bear 
the transference to strong spirit. To obviate these inconveniences the 
author has adopted the principle of Overton’s method.* The objects, 
already stained, are removed from alcohol to a solution of 100 parts 
94 per cent, spirit and of 10 parts Venetian turpentine. The preparation 
is then placed in an air-tight glass capsule in the presence of chloride of 
calcium, by which means the turpentine is slowly concentrated by the 
removal of the spirit and water. 
The glass capsules and other vessels employed in the manipulation 
should have tall sides, e. g. 2 cm. high to 1 • 5 cm. diameter, and 2 • 5 cm. 
high to 2 cm. diameter. The edge inside and out should be smeared 
with paraffin ; this is easily done by just dipping the top of the capsule 
into molten paraffin and allowing it to set ; the width of the paraffin rim 
should be 3-4 mm. These precautions prevent the turpentine from 
running up the inside and then down the outside of the capsule. 
In these small capsules the object is immersed in the turpentine 
solution, and then these placed inside a larger closed capsule, the dia- 
meter of which is 8-10 cm., and the height 3*5-4 cm. In a few days 
the object will be found saturated and surrounded by thick turpentine, 
and suffering from no distortion. 
Tissues which crumple up when placed in strong alcohol are treated 
by Overton’s glycerin method. The object is placed in a mixture of 
90 parts of water and 10 parts of glycerin ; by slowly extracting the 
water the glycerin is inspissated, and this in its turn is removed with 
strong or absolute alcohol. The concentration is hastened by using the 
sulphuric acid exsiccator. 
Preparations thus treated may, after 12-24 hours’ immersion in 
spirit, be mounted straight away in the Venetian turpentine. If, how- 
ever, they will not bear this, the procedure originally noticed must be 
adopted. 
C6) Miscellaneous. 
An Inexpensive Reagent Block.! — Prof. J. H. Pillsbury says : — 
“ A frequently expressed need of some convenient and inexpensive 
block or case in which to place the reagents and apparatus used in the 
biological laboratory, leads me to describe the form I have used for 
some time (fig. 69). 
It is a plain whitewood block, 15 cm. square and 4 cm. thick. On 
the upper side of this three grooves are cut, each 1 • 5 cm. deep. The 
first is 1 cm. from the edge, and 1 cm. wide. The second is 1 cm. from 
it, and 3 * 5 cm. wide. The third is 1 cm. from it, and 2 cm. wide. Into 
one end there is glued a closely-fitting block 1 cm. long, and in the 
other end one 5 cm. long, leaving a trough for slides about 9 cm. long. 
In the place where this last block is glued is bored a hole 1 * 5 cm. 
in diam. and 1 cm. deep, into which tightly fits a paper pill-box for 
covers. The remainder of the block is provided with two rows of five 
* See this Journal, 1890, p. 535. 
t Amer. Mon. Micr. Journ., xi. (1890) p. 2. 
