FALSIFICATIONS. 
277 
upon the quality of a rhubarb, he must attend to its pulveri- 
zation himself. 
Particular care is required in the selection of Croton Oil; 
complaint has been made by physicians against some that is 
as powerless as sweet oil in its application as a rubefacient. 
The best is that imported from India, a drop or two of which, 
applied to the skin, produces an erysipelatous eruption. 
Arrow Root is another article which requires scrutiny 
if you would not have common fecula palmed upon 
you. How often is potato starch sold for genuine Bermuda 
arrow root? To the unaccustomed eye the difference is not 
easy of detection. Genuine arrow root is exhibited in the 
form of very small pearl-white friable lumps, intermingled 
w T ith fine powder, from attrition of the grosser particles. It 
differs from potato starch in having a bluish cast, and the 
edges of the grains are translucent, while the other feculasare 
generally in larger lumps, of a dull white color, with a yel- 
lowish cast. While the West India arrow root is always 
without any sensible odor; the kind coming from Florida, has 
a rancid butter smell. This I have many times perceived in 
a number of lots known to have come from this source: ex- 
posure to the air did not dissipate this smell. Bermuda 
arrow root makes a very transparent and tenacious jelly. Po- 
tato starch and Florida arrow root do not make so clear and 
consistent a jelly, and decompose much sooner. Pressed 
between the thumb and finger, the true arrow root falls to 
powder, while potato starch offers greater resistance, and 
emits a crackling noise. The grains of arrow root, examined 
through a microscope, are transparent, and appear composed of 
minute shining crystals. The disparity in the prices and the 
easy substitution of the cheaper for the better, with but little 
chance of detection, makes the starch common throughout the 
country. As that from Bermuda commands as high a price 
as fifty cents, it is confined to the large cities; the others may 
be obtained at prices ranging from fifteen to thirty cents per 
pound. 
VOL. iv. — no. iv. 36 
