PHARMACY. 
loss of their virtue. There are several snb- 
staYices, however, of this kind, which can- 
not be conveniently taken in powder ; bit- 
ter, acrid, foetid drugs are too disagreeable ; 
emollient and mucilaginous herbs and roots 
are too bulky ; pure gums cohere, and 
become tenacious in the mouth : fixed alka- 
line salts deliquesce when exposed to the 
air, and volatile alkalies exhale. Many of 
the aromatics, too, suffer a great loss of 
their odorous principles when kept in pow- 
der; as in that form they expose a much 
larger surface to the air. 
The dose of powders, in extemporaneous 
prescription, is generally about half a 
drachm : it rarely exceeds a whole drachm ; 
and is not often less than a scruple. Sub- 
stances which produce powerful effects in 
smaller doses are not trusted to this form, 
unless their bulk be increased by additions 
of less efficacy ; those which require to be 
given in larger ones are better fitted for 
other forms. 
The usual vehicle for taking the lighter 
powders, is any agreeable thin liquid. The 
ponderous powders, particularly those pre- 
pared from metallic substances, require a 
more consistent vehicle, as syrups ; for 
from thin ones they soon subside ; resinous 
substances likewise are most commodiously 
taken in thick liquors, for in thin ones they 
are apt to run into lumps, which are not 
easily again soluble. 
Pulvis aloes cum canella, Lond. powder 
of aloes with canella. 
Pulvis aloeticus cum guaiaco, Lond. pow- 
der aloetic with guaiacum. 
Pulvis aloeticus cum ferro, Lund, powder 
aloetic with iron. 
Pulvis aromaticiis, Lond. Dnbl. powder 
aromatic. 
Pulvis asari compositus, Lond. Dubl. 
powder of asarabacca compound. 
Pulvis cretse compositus, Lond. pulvis 
carbonatis calcis comp. Edin. powder of 
chalk, compound. 
Pulvis cretae compositus cum opio, Lond. 
powder of chalk, compound with opium. 
Pulvis chelarura cancri compositus, Lond. 
powder of crab’s claws, compound. 
Pulvis cenissae compositus, Lond. pow- 
der of ceruse, compound. 
Pulvis contrayerv® comp. Lond. powder 
of contrayerva, compound. 
Pulvis ipecacuanhae comp. Lond. pulvis 
ipecacuanhae et opii. Edin. powder of Do- 
ver’s. 
Pulvis myrrbae comp. Lond. powder of 
myrrh compound. 
Pulvis scammonii comp. Lond. Edin. 
Dubl. powder of scammony, compound. 
Pulvis scammonii comp, cum aloe, Lond. 
powder of scammony compound with 
aloes. 
Pulvis scammonii comp, cum calomelane, 
Lond. powder of scammony with calo- 
mel. 
Pulvis sen® compositus, Lond. powder 
of senna, compound. 
Pulvis sulphatis alumin® comp. Edin. 
powder of styptic. 
Pulvis tragacanth® compositus, Lond. 
powder of tragacanth, compound. 
Class XXI. Confectiones. Confections. 
Under this title we include all those pre- 
parations which have hitherto been loosely 
denominated conserves, electuaries, and 
confections ; the difference in the prepara- 
tion of which being too trifling for distinct 
heads. 
Confections are, for the most part, com- 
positions of recent vegetable matters and 
sugar, beaten or otherwise mixed together 
into an uniform mass. The sugar should be 
pounded by itself, and passed through a 
sieve before it be mixed with the vegetable 
mass, for without this it cannot be properly 
incorporated. It is obvious that, from the 
large admixture of sugar, only substances 
of considerable activity can be taken with 
advantage in this form. Conserves are 
hence, for the most part, only auxiliary to 
medicines of greater activity ; as, for ex- 
ample, for reducing into boluses or pills 
the more ponderous powders, as calomel, 
oxides of iron, and other mineral prepa- 
rations. 
Electuaries are composed chiefly of pow- 
ders mixed up with syrups, &c. into such a 
consistence, that the powders may not se- 
parate in keeping, that a dose may be easily 
taken up on the point of a knife, and not 
prove too stiff to swallow. 
Electuaries receive chiefly the milder 
alterative medicines, and such as are not 
ungrateful to the palate. The more power- 
ful drugs, as cathartics, emetics, opiates, 
and the like (except in officinal electuaries 
to be dispensed by weiglit), are seldom 
trusted in this form, on account of the un- 
certainty of the dose : disgustful ones, 
acrids, bitters, feetids, cannot be conveni- 
ently taken in it ; nor is the form of an 
electuary well fitted for the more ponder- 
ous substances, as mercurials, these being 
apt to subside on keeping, unless the com- 
position be made very stiff. 
