ARSENIC 



Arrowroot is brought into the market from Bermuda, St. Vincent, Jamaica, Brazil, 

 the East Indies, Natal, and Sierra Leone. It is subject to a duty of 4s. per cwt. The 

 Bermuda arrowroot was in 1865 sold wholesale at Is. 2d. 

 the pound, the other sorts varying from 2%d. to 6d. 



The uses of arrowroot are too well known and acknow- 

 ledged to require recounting here. It is the most elegant 

 and the richest of all the feculas. Liebig places the 

 powers of arrowroot, as a nutriment to man, in a very re- 

 markable point of view, when he states that 15 pounds of 

 flesh contain no more carbon for supplying animal heat 

 by its combustion into carbonic acid in the system than 4 

 pounds of starch ; and that if a savage, with one animal 

 and an equal weight of starch, could maintain life and 



health for a certain number of days, he would be compelled, I J 



if confined to flesh alone, in order to procure the carbon 



necessary for respiration during the same time, to consume five such animals, All 



the starches arc readily converted into sugar and fat, but they are low in their flesh- 

 producing power. 



In commerce, the term arrowroot is frequently used generically to indicate a starch 

 or fecula, as: East India, arrowroot, prepared from the Curcuma angustifolia. 

 Brazilian arrowroot or Cassava, the fecula of Jatropha manihot. English arrowroot, 

 the starch of the potato (Solatium tuberosum). Portland arrowroot, a white 

 amylaceous powder, formerly prepared in tho Isle of Portland, from the Arum 

 maculatum, tho common Cuckoo-pint, called also Wake-robin and Lords and Ladies. 

 Tahiti arrowroot, the fecula of Tacca oceanica, which has been imported into London 

 and sold as ' arrowroot prepared by the native converts at tho missionary stations in 

 the South Sea Islands.' 



The presence of potato-starch in arrowroot, with which it is often adulterated, 

 may bo discovered by the microscope. Arrowroot consists of regular ovoid particles 

 of nearly equal size, whereas potato-starch consists of particles of an irregular ovoid 

 or truncated form, exceedingly irregular in their dimensions, some being so large as 

 3i5oth of an inch, and others only ^oth. Their surfaces in the arrowroot are 

 smooth and free from tho streaks and furrows to be seeji in the potato-particles by a 

 good microscope. The arrowroot, moreover, is destitute of that fetid unwholesome 

 oil extractable by alcohol from potato-starch. But the most convenient test is dilute 

 nitric acid of riO (about the strength of single aquafortis), which, when triturated in 

 a mortar with the starch, forms immediately a transparent, very viscid paste or jelly. 

 Flour-starch exhibits a like appearance. Arrowroot, however, forms an opaque 

 paste, and takes a much longer time to become viscid. 



AK.SEW ATES. Compounds of arsenic acid with alkaline and metallic bases 



ARSENIC, derived from the Greek apfftvHtbv, masculine, a name applied to orpi- 

 mont on account of its potent powers. Arsenic occurs native, in veins, in crystalline 

 rocks, and the older schists ; it is found in tho state of oxide, and also combined with 

 sulphur, when it is known under the names of yellow and red arsenic (orpiment and 

 realgar). Arsenic is associated with a great many metallic ores ; in this country chiefly 

 with those of tin, but on the Continent arsenical cobalt is the chief source of the 

 compounds of arsenic. 



