662 
THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. [February 17, 1872. 
enables the analyst in many, indeed in most cases, 
to decide upon the genuineness or not, of the article. 
To apply this test requires that the starch gra¬ 
nules be isolated, and prepared for observation—a 
matter of little difficulty, as starch is easily diffu¬ 
sible through water, and remains suspended long 
after the other constituents of the potato have sub¬ 
sided. Professor Attfield* gives very simple direc¬ 
tions (‘ Chemistry,’ pp. 308-9) for the preparation 
of potato-starch :—“ Hasp or grate or scrape a por¬ 
tion of a clean raw potato, letting the pulp fall on to 
a piece of muslin placed over a small dish or test- 
glass, and then pour a slow stream of water over 
the pulp.' Minute particles or granules of starch 
pass through the muslin, and sink to the bottom of 
the vessel.” The plan which I have myself adopted 
is substantially that followed by those who prepare 
arrowroot and sago for the market, and is perhaps 
on this account preferable. Pound the potato, 
other tuber, grain or starch bearer in a mortar to a 
pulp ; throw the pulp into a vessel of water, and, 
having stirred it well, allow it to subside ; collect 
the fibrous matter (both that which chances to swim 
as scum and that which subsides before the starch), 
and remove it. Allow the starch to subside; pour 
off the supernatant water; fill up the vessel, and 
pour the milky water through a piece of muslin, and 
allow the now nearly pure starch to subside. Wash 
it once or twice, and then collect. Dry, and put 
into a corked bottle. The resultant starch is “ com¬ 
mercial^” pure,f and in a fit state for microscopical 
examination. But, as most beginners have disco¬ 
vered, it is of little use to examine dried starch an 
naturel by either reflected or transmitted light. It 
is necessary to immerse it in some fluid, than which 
nothing is better than equal parts of Price’s best 
glycerine, sp. gr. 1240, and water. The use of a 
quarter-inch object is desirable. 
The analyst should make careful measurement of 
a number of the granules, and take the mean of the 
whole. Here we may profitably consider the sim¬ 
plest means by which this may be effected. Hr. L. 
Beale recommends the use of the camera lucida or 
neutral-tint reflector and the stage micrometer as 
affording the most “ simple and efficacious manner 
of measuring objects.” The neutral-tint reflector is 
simply a piece of neutral-tinted glass arranged at an 
angle of 45° to the eye-piece, and can be procured of 
any optician at a cost of about 7 s. (id. The stage mi¬ 
crometer (cost 5s.) consists of a piece of glass whereon 
are ruled lines separated by thousandths of an inch 
(100 and 1000 per inch are most commonly used). 
The micrometer is arranged on the stage of the 
instrument, and the microscope inclined on its axis 
to the horizontal, the neutral-tint being slipped into 
its place on the eye-piece. The observer, looking 
down into the reflector, sees apparently on a piece 
of white paper placed on the table beneath it the 
outlines of the micrometer divisions, and can with 
the greatest exactness trace them with pen and ink 
* I must call attention to an important error into which 
Professor Attfield has fallen. The Professor says that wheat- 
starch, viewed by polarized light, does not 6how the black 
cross given by potato-starch. The black cross of wheat- 
starch is most marked and characteristic. The effects of the 
two starches upon, a selenite differ slightly. Rice-starch also 
gives a “cross.” 
t Treatment with alcohol and ether is necessary to render 
it chemically pure, but would be obviously out of place for 
our purpose. 
or pencil. A set of these tracings should be made 
from each objective, and either lithographed or 
struck off' by letterpress, that a copy may be affixed 
to each drawing made from the same objective. 
Removing the micrometer from the stage, a slide of 
the starch is substituted, and the outlines of a num¬ 
ber of the granules carefully traced by the side of 
the outlined micrometer divisions* It is clear that 
the ascertainment of the exact size of each granule 
is a matter of the greatest facility. Ramsden’s and 
Jackson’s micrometers are supplied with “first-class 
stands” for the same purpose, and possess many 
advantages, but in point of inexpensiveness and 
simplicity are not to be compared with the very 
simple plan propounded by l)r. Beale. If only 
rough measurements are required, it will suffice to 
place an ordinary rule, divided to one-tentli of an 
inch, on the stage beside the object or micrometer, 
and to compare it or the micrometric divisions with 
the divisions on the rule by observing the latter 
with the left eye, whilst the right is engaged at the 
microscope. This simplest of plans is not, how¬ 
ever, sufficiently accurate to be used in microscopic 
analysis. 
Specimens of the starch as prepared should be 
mounted in syrup, glycerine, and for examination 
by polarized light in ‘ dammar.’* The specimen in 
syrup will be found serviceable in the examination 
of many samples of honey; that in glycerine will 
show the modifying action of a dense fluid upon the 
granule. But for general comparison it is essential 
that a portion should be taken from the stock-bottle; 
for no medium, so far as I know, can be relied 
upon for the preservation of starch in its normal 
condition as to size and shape. Careful study 
should be made of the changes induced by moist 
and dry heat, and preparations of each should be 
put up in dammar and in glycerine (25 per cent, 
water), that the student may be prepared to recog¬ 
nize the granule under all the modifications pro¬ 
duced by boiling, roasting, and even fine grinding. 
We have dealt thus fully with potato-starch, be¬ 
cause it is a t}q>e of all the starches, and is, in addi¬ 
tion, the one most commonly met with as an adul¬ 
terant, and the adulterant of adulterants. 
(To be continued.) 
CRYSTALLIZED ACONITOTE.f 
BY M. DUQUESXEL. 
(Concluded from page 025.) 
Toxicology of Aconitine. 
The next section of the memoir is devoted to the 
subject of poisoning by aconitine, which is similar in 
its physiological effects to aconite. One of the most 
characteristic of these effects is the pricking or tingling 
sensation, analogous to that produced by pyrethrum 
root, which is experienced in the mouth after the 
disappearance of the bitter taste. The sensation is 
produced in a few minutes by very small doses, or 
traces onty, of pure aconitine, and sometimes lasts 
* So many microscopists have a difficulty in procuring 
“ microscopical dammar,” that it will, perhaps, be of service 
to say that it may be procured in a very convenient form of 
Mr. Walter White, M.P.S., Norwich. 
f De l’Aconitine Cristallise et des Preparations d’Aconit, 
Etude Chimique et Pharmacologique. Par H. Duquesnel, 
Pbarmacien de Premiere Classe. Paris : Bailliere et Fils. 
