528 
THE PRINCIPLES OF BOTANY. 
forms a gum possessing the same characters as the milky 
juice itself. 
Of British spurges Bentham describes twelve species, while 
Dr. Syme makes fifteen. Many of these are common weeds, 
hut at the same time an attentive examination of their 
structure will well repay the inquirer. 
The Euphorbia Lathyrus —Caperspurge—is a very hand¬ 
some species which from long cultivation in gardens has 
become naturalised. It was grown for use in the same 
manner as capers. Dr. Pereira says: “ The capsules are 
pickled and used as a substitute for capers, which they 
resemble in size, appearance, and pungency. When recent 
they are certainly acrid and poisonous; and it is probable, 
therefore, that the pickling process lessens or destroys their 
virulence ; but the free use of the pickled fruits is dangerous. 5 ’ 
All our wild species emit a thick milky juice on being 
broken, and the commoner sorts, E. peplus, dwarf spurge, E. 
helioscopia , sun spurge, and some others, are constantly 
appealed to by the rustic for the cure of warts, which is 
effected by merely touching the excrescences a few times with 
the exuding milk; it seems to act as a vegetable escharotic 
and vesicant. The exotic species contain most powerful 
medicinal principles. The Euphorbia officinarum , a most 
interesting cactiform plant, yields a drug known as “ Gum 
Euphorbium,” of which more anon. 
The interest of the plant to the vegetable physiologists con¬ 
sists in its total absence of leaves, which organs are repre¬ 
sented by a series of black spines which are placed at more 
or less regular intervals on a lohated cactus-like stem which 
is not only green and succulent, but is so covered with stomata 
that, as in the Cacti themselves, the stem seems to be modified 
to perform the leaf function. In this as in several of the 
species of our greenhouses what appears to be coralloid 
flowers are after all only coloured involucres, from the centre 
of each of which proceeds the stalked ovarium , consisting of 
three cells, each with a single suspended seed. Our common 
wild forms have the same structure, but being green and 
inconspicuous it escapes notice, whereas some foreign forms 
of Euphorbia and its ally Poinsettia are beautiful and flower¬ 
like rather from the surroundings of the floral organs than 
from the organs themselves. The gum from the E. officinarum, 
according to Pereira, is procured as follows • 
“ The inhabitants of the lower regions of the Atlas range 
make incisions in the branches of the plant, and from these a 
milky juice exudes lohich is so acrid that it excoriates the 
fingers when applied to them. This exuded juice hardens by 
