148 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
Agitate thoroughly, and let stand until these two fluids separate, then 
from the water decant the turpentine (which this time will form the 
upper layer), and finally, mix with the turpentine about 1 oz. of pow- 
dered starch, and filter through paper. 
By pursuing the foregoing plan any one may secure a pure, limpid, 
and brilliant turpentine. The alcohol used in rectifying it need not 
be wasted, as it will do to bum, to clean slides, or for other purposes. 
I usually make a large quantity, and recover the alcohol by distillation. 
(6) Miscellaneous. 
Biological Examination of Potable Water.* — Mr. G. W. Rafter 
describes a modification of Prof. W. T. Sedgwick’s method of deter- 
mining the number of organisms in drinking water. The water is 
filtered through a short column of fine sand in the stem of a funnel, the 
sand being supported on a plug of wire-cloth placed beneath it. The 
sand retains the whole of the organisms contained in the water. After 
the completion of the filtration, the sand is washed with distilled water 
into a test-tube, and shaken, when all the sand falls to the bottom and 
the organisms remain uniformly distributed through the water. A 
definite quantity of this is taken out by a pipette and placed in a cell of 
known dimensions. The enumeration of the organisms is accomplished 
by transferring the cell to the stage of the Microscope and examining 
with the aid of the micrometer. 
Tests for Glucosides and Alkaloids.t — Herr A. Rosoll gives the 
following tests for berberin and cytisin : — Berberin dissolves in con- 
centrated nitric acid with a reddish-brown colour, and may then be 
precipitated in star-like groups of crystals of berberin nitrate by the 
successive action of alcohol and nitric acid ; or it can be precipitated as 
characteristic green capilliform crystals by potassium iod-iodide from 
the alcoholic solution ; the crystals being again soluble in sodium 
hyposulphate. It occurs in all the organs of mature plants of Berberis 
vulgaris. Cytisin occurs in all parts of the laburnum, but there are 
only traces in the leaves or flowers. It gives a red-brown precipitate 
with potassium iod-iodide, leaf-like groups of crystals with picric acid ; 
a light reddish-yellow solution with sulphuric acid, which becomes 
yellow, brown, and finally green, on addition of a small piece of potas- 
sium bichromate ; a yellow turbidity with phosphor-molybdic acid. 
Tests are also given for coniferin, phloroglucin, vanillin, salicin, 
syringin, hesperidin, solanin, saponin, tannin, veratrine, strychnine, 
brucine, colchicine, nicotine, aconitine, and atropine. The author asserts 
that strychnine occurs in solution in the drops of oil held in solution 
in the endosperm-cells, and not, as sometimes stated, in the thickenings 
of the cell-walls. 
Materials of the Microbe-Raiser.:}: — Dr. S. Hart makes the fol- 
lowing somewhat amusing remarks : — “ Some of the means and methods 
* Proc. Rochester (X.Y.) Acad. ScL, 1890, 10 pp. and 4 figs. 
t ‘ Ueb. d. mikrochemisclen Xachweis d. Glycoside u. Alkaloide,’ Stockerau, 1890, 
25 pp. See Bot. Centralbl., xliv. (1890) p. 44. 
X -‘Invisible Assailants of Health,” ‘Popular Science Monthly.’ See Amer. 
Mon. Micr. Joum., xi. (1890) p. 232. 
