HEL. 
garden-snail, shell imperforate, globular, 
pale, with broad interrupted brown bands : 
this species inhabits the garden and or- 
chard in most parts of Europe ; it abounds 
with a viscid slimy juice, which it readily 
gives out by boiling in milk and water, so 
as to render them thick and glutinous, and 
the compound, especially with milk, is 
reckoned efficacious in consumptive cases. 
Snails are very destructive to wall-fruit : 
lime and ashes sprinkled on the ground will 
keep them away, and destroy the young 
brood. Fruit, already bitten, should not 
be taken off the tree, for they will not 
touch the other, till they have wholly eaten 
this, if left for them. The eyes of snails 
are lodged in their horns, one at the end of 
each horn, which they can retract at plea- 
sure. The manner of examining these eyes, 
which are four in number, is this : when the 
horns are out, cut off nimbly the extremity 
of one of them, and, placing it before the 
microscope, you may discover the black spot 
at the end to be really a semiglobular eye. 
The dissection of this animal is very cu- 
rious ; for, by this means, the microscope 
not only discovers the heart beating, just 
against the round hole near the neck, which 
seems the place of respiration ; but also the 
liver, spleen, stomach, and intestines, with 
the veins, arteries, mouth, and teeth, are 
plainly observable. The intestines of this 
creature are green, from its eating herbs, 
and are branched all over with fine capillary 
white veins; the mouth is like a hare’s or 
rabbit’s, with four or six needle-teeth, re- 
sembling those of leeches, and of a sub- 
stance like horn. Snails are all hermaphro- 
dites, having both sexes united in each indi- 
vidual ; they lay their eggs with great care 
in the earth, and the young ones are hatch- 
ed with shells completely formed. Cutting 
off a snail’s head, a little stone appears, 
which is supposed to be a great diuretic, 
and good in all nephritic disorders : imme- 
diately under this stone, the heart is seen 
beating ; and the auricles are evidently dis- 
tinguishable, and are membranous, and of a 
white colour, as are also the vessels which 
proceed from them. So small an animal as 
the snail, is not free from the plague of sup- 
porting other smaller animals on its body ; 
and, as in other animals, we find these se- 
condary ones either living on their surface 
as lide, &c. or only in the intestines, as’ 
worms ; it is very remarkable, that the snail 
is infested in both these manners, lice be- 
ing found sometimes on the surface of its 
body, and worms sometimes within its in- 
HEL 
testines. There is a part of the common 
garden snail, and of other of the like kinds, 
commonly called the collar; this surrounds 
the neck of the snail, and is considerably 
thick, and is the only part that is visible 
when the animal is retired quietly into its 
shell : in this state of the animal, these in- 
sects which infest it are usually seen in con- 
siderable numbers, marching about very 
nimbly on this part; besides, the snail, 
every time it has occasion to open its anus, 
gives them a place by which to enter into 
its intestines, and they often seize the op- 
portunity. 
HELLEBORUS, in botany, English hel- 
lebore, a genus of the Polyandria Polygynia 
class and order. Natural order of Multisi- 
lique. Ranunculaceae, Jussieu. Essential 
character: calyx none ; petals five, or more ; 
nectary two-lipped, tubular ; capsules many- 
seeded. There are seven species. 'The 
hellebores are all hardy, herbaceous peren- 
nials, with compound leaves, digitate, pe- 
date, palmate, or ternate ; the flowers have 
only a single coVer ; they grow either seve- 
ral together, at the ends of the stalk and its 
subdivisions, with a single bracte to each 
pedicle ; or single on a scape, naked, or 
with a leaf for an involucre. They appear 
early in the spring, and often in the winter. 
The root of this plant is tuberous; at first 
it has no taste, but in a short lime, a strong 
acridity becomes sensible to the mouth and 
throat. By distillation, an oil is obtained 
which is extremely poisonous : a one similar 
in its effects may be obtained from many 
plants. 
HELM, in naval architecture, a long and 
flat piece of timber, or an assemblage of 
several pieces, suspended along the hind 
part of a ship’s stern-post, where it turns 
upon hinges to the right or left, serving to 
direct the course of the vessel, as the tail of 
a fish guides the body. The helm is usually 
composed of three parts, viz. the rudder 
the tiller, and the wheel, except in small 
vessels, where the wheel is unnecessary. 
As to the form of the rudder it becomes . 
gradually broader in proportion to its dis- 
tance from the top, or to its depth under 
the water. The back, or inner part of it, 
which joins to the stem post, is diminished 
into the form of a wedge throughout its 
whole length, so as that the rudder may be 
more easily turned from one side to the 
other, where it makes an obtuse angle with 
the keel. It is supported upon hinges, of 
which those that are bolted round the stern- 
post to the after extremity of the ship are 
