26 
ON DRUG-GRINDING. 
cine depend upon these volatile parts, the product must be 
injured by the process to which it is submitted. Thus myrrh, 
valerian, cardamoms, cinnamon, and spices generally, lose 
some of their efficacy in being reduced to fine powder. 
But a large proportion of our drugs are not subject to de- 
terioration from loss of volatile constituents ; and in these 
cases, if care be exercised in conducting the process of dry- 
ing, the powder obtained by the usual method of operating 
will possess all the medicinal properties of the crude mate- 
rials. Rhubarb, jalap, ipecacuanha, colocynth, scammony, 
gamboge, and many other drugs, are not necessarily injured 
in the process of powdering. 
There are some drugs which not only suffer no injury in 
being powdered, but which actually contain, when pulve- 
rized, a larger proportion of the active constituents than 
were present in the crude unpowdered substance. This 
arises from the circumstance that the less active parts are 
separated and rejected during the process. Thus, for in- 
stance, the powder of ipecacuanha, if properly prepared, 
contains more of the emetic principle than the root from 
which it is made. The principle upon which the emetic 
property of ipecacuanha depends, exists chiefly on the cor- 
tical part of the root, and as this is the most easily pulveriza- 
ble, it passes first through the sieve, while the less active 
ligneous part, being more tough, remains to the last, and 
should be rejected as gruffs. 
Besides the loss of water and other volatile constituents, 
which are driven off in the drying-room, there is also neces- 
sarily a dissipation and loss to certain extent of solid parti- 
cles of powder, which are diffused through the atmosphere 
of the room in which the pulverization is conducted, or 
which adhere to the apparatus. 
With these exceptions the product, including the gruffs or 
unsifted part, ought to be identical with the substance it re- 
presents; that is to say, should consist of the same particles, 
and no others, in the same chemical condition as they existed 
in previously to the process of powdering. 
