MOHR AND REDWOOD'S PRACTICAL PHARMACY. 225 
going any alteration, being completely protected by their 
metallic covering. 
<c The covering of pills with gelatine is the most elegant 
and efficient method of fulfilling the objects contemplated in 
the processes now under notice. A pill when thus covered, 
has a clean, shining surface, which is dry, hard, and not at 
all sticky. No powder is, therefore, required in addition to 
the gelatin. The ingredients of the pill being enclosed in 
a gelatinous case, are preserved from the action of the air, 
and, to a certain extent, are prevented from undergoing 
volatilization; moreover, the pill itself may be swallowed 
without perceiving taste or smell. 
"The folio wing is the method of covering pills with 
gelatin: 
" In the first place, a solution of gelatin is prepared, con- 
sisting of one part of gelatin and two parts of water. This 
solution may be made in 
a little water-bath such as 
that represented in fig. 
28. The gelatinous mix- 
ture is put into the vessel 
«, where it is surrounded 
by hot water contained 
in the outer vessel, and 
the heat is maintained by 
the gas-lamp c, while the 
steam escapes through the 
tube b. 
" The pills are now 
made as in the preceding 
case, without using any 
powder, or if powder be 
used on the machine, it 
must be subsequently 
wiped off the pills. 
"A number of straight, pointed wires are in the next 
