30 
ON DRUG-GRINDING. 
weight of the substance ground, for loss in the process. 
Thus, if a hundredweight of rhubarb were sent to the drug- 
mills, 108lbs. of powder including the gruffs, would be 
returned. It matters not what condition the rhubarb might 
be in, the drug-grinder would be expected to produce 
lOSlbs. of powder from 112lbs. of raw material. The same 
allowance would also be made, unless otherwise agreed 
between the parties, for all other drugs which required dry- 
ing previously to their being powdered. In some cases the 
practice appears to have been to receive 116lbs. of the un- 
dried drug, and to return 112lbs. of dry powder. This is 
called the four per cent, system, four pounds being the al- 
lowance for loss upon every hundredweight of substance 
powdered. Some substances, however, such as cream of 
tartar and sulphuret of antimony, do not require to be dried 
before being powdered, and the allowance for loss on these 
substances is only two per cent. 
This, which is commonly called the per centage, or four 
per cent, system, was at one time generally, if not uniformly, 
adopted by the drug-grinders of London, and although it 
has to a great extent been relinquished, having been wholly 
departed from by some houses, and partially by others, yet 
there are those who still contend that the specified allow- 
ance is a fair average of the loss necessarily occurring in the 
process of drug-grinding. 
Being convinced of the injurious tendency of the four 
per cent, system, I applied to several parties engaged in the 
business of drug-grinding for information on the subject, 
and am indebted to one of these parties for a statement ex- 
tracted from their books, showing the loss sustained in 
powdering drugs at their mills. Every drug powdered at 
the establishment alluded to, is weighed when received at 
the mill, and the ground products, consisting of fine powder 
and gruffs, are again weighed before being returned to the 
druggist. These weights are all entered in their books, a 
separate account being kept for each kind of drug, so that 
by taking an average of the results upon large quantities, 
