\ 
CONVOLVULUS JALAPA. 
203 
«re numerous, slender, herbaceous, climbing, and twine round other 
bodies for support, and rise to Ihe height of eight, ten, or more 
feet; the leaves are petioled, serrated, smooth on the upper sur- 
face and hoary underneath, but vary in shape ; the lower leaves are 
generally heart-shaped or lobed ; the upper ones oblong and acute ; 
the flowers are large, and stand upon short axillary peduncles, each 
peduncle bearing one or more flowers; the calyx consists of five oval 
concave leaves ; the corolla is monopetalous, bell-shaped, plaited 
and entire, of a pink or rose externally, and a deep purple within ; 
the filaments are slender, and vary a little in length, the base of the 
filaments are covered with short purple hair, and inserted into 
the corolla ; the anthers are large, oblong, tapering, and of a yellow 
colour ; the germen is oval, the style slender, stigma roundish and 
two-lobed. 
Sensible and Chemical Properties. The root of jalap as 
imported is in the form of transverse slices, or in raund lumps, 
which are covered with a wrinkled bark, of a blackish colour; inter- 
nally they are of a dark grey, marked with darker or blackish 
stripes. Jalap is heavy, hard, and solid ; its smell is somewhat 
nauseous, and its taste nauseous and acrid ; when swallowed it 
affects the throat with a sense of heat, and occasions a copious dis- 
charge of saliva ; when powdered it has a yellowish colour. The 
constituents of jalap are resin, extract, starch, and woody fibre, the 
proportion of which, vary in different varieties of the root. 
• Slices of briony root are said to be frequently mixed with those 
of jalap, but these may be readily distinguished (by the careful exa- 
mination of each separate piece) by their whiter colour and less 
compact texture. 
Medical Properties and Uses. Jalapine, this is a new 
vegeto-alkaline principle lately discovered in the root of jalap, by 
Mr. Hume, jun,, of Long Acre. Of its action on man and animals, 
we are unacquainted, not having learnt that any experiments have 
been yet instituted to ascertain its effects. Mr. Hume considers 
that one ounce of jalap will, on careful treatment, afford about five 
grains of this substance. Mr. Hume's process is as follows ; — 
coarsely powdered jalap is macerated for twelve or fourteen days in 
strong acetic acid ; a highly-coloured tincture is thus obtained, 
which, when filtered, is super-saturated with ammonia, and the 
mixture violently shaken ; a sabulous deposit rapidly falls, and a few 
crystals form on the sides of the vessel. The deposit and crystals 
are collected and washed with distilled water, again dissolved in a 
small quantity of concentrated acetic acid, and re-precipitated by 
