z 
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344 STOMACH. 
tion by food, its singular smallness is a beautiful 
provision to prevent painful or injurious inter- 
ference with the process of respiration. “ The 
situation of the stomach,” remarks Youatt, “ will 
at once explain the reason why a horse is so much 
distressed and sometimes irreparably injured, if 
worked hard immediately after a full meal. The 
stomach must be displaced and driven by every 
contraction of the diaphragm or act of inspira- 
tion, and in proportion to the fulness of the 
stomach will be the weight to be overcome, and 
the labour of the diaphragm, and the exhaustion 
ofthe animal. If the stomach is much distended, 
it may be too weighty to be forced sufficiently 
far back to make room for the quantity of air 
which the animal in a state of exertion requires. 
Hence the frequency and labour of the breath- 
ing, and the quickness with which such a horse 
is blown, or possibly destroyed. Hence also the 
folly of giving too full a meal, or too much water, 
before the horse starts on a journey or for the 
chase, and, in like manner, the absurdity and 
danger of that unpardonable custom of some 
grooms to gallop the horse after his drink, in 
order to warm it in his belly, and prevent gripes.” 
The stomach has two surfaces, which may be 
called its sides, though one is posterior, and the 
other anterior,—and two extremities, a larger 
and a smaller,—the latter of which receives the 
cesophagus or gullet, while the former ends in 
the duodenum, and, when the stomach is dis- 
tended, extends farther back than the other. 
The stomach is externally covered by the peri- 
toneum, which adheres closely to it by means of 
its cellular membrane; and it has within this a 
coat or system of muscular fibres, which are 
stronger than those of the stomachs of oxen and 
sheep. These fibres run in various directions, 
but are principally longitudinal and circular ; 
and the latter are very thick and strong around 
the extremity in which the gullet terminates. 
The inner covering of the stomach consists of 
two portions, a cuticular and a villous. The 
cuticular portion extends over nearly one half, 
and is possessed in common with the horse by 
only such other animals as live chiefly on grain; 
and it may be considered as, in a slight degree, 
a kind of gizzard, acting compensatorily for the 
want of power of thorough mastication. The 
horse, notwithstanding the grain-grinding struc- 
ture of his teeth, is urged by the wants of his 
system to feed greedily and swallow hastily, so 
that he does not sufficiently masticate his food ; 
and he therefore enjoys a peculiarity of coating 
over his stomach which acts in a triturating way, 
and ensures the digestion of half ground grain. 
The insensibility of the cuticular coat occasions 
many medicinal substances which act with great 
power or virulence on man, such as emetic tartar, 
verdigris, sugar of lead, blue vitriol, white vitriol, 
and arsenic, to have little effect on the horse. The 
villous coat is much more extensive than. the 
muscular, and is thrown into comparatively large 
STONE. 
folds; and these are largest toward the gullet, 
and become less toward the duodenum, and form 
there a kind of valve which prevents a return of 
the food and regulates its passage out ; and they 
afford in the aggregate an ample secreting sur- 
face for the gastric juice, and everywhere apply 
it equally to all the parts of the substances which 
are undergoing digestion. The terminating fibres 
of the gullet pass obliquely through part of the 
muscular and cuticular coats, and then arrange 
themselves at the orifice in a manner interme- 
diate between that of a valve and that of a 
sphincter muscle, so as to present an insuperable 
obstacle to the regurgitation of food. A horse, 
therefore, cannot vomit. 
STOMACHIC. A medicine which strengthens 
the stomach and excites appetite. In veterinary 
practice, it is closely allied to a cordial, but pro- 
duces a more durable effect. 
STOMACH (Inriammatron or). See Gastritis 
and Braxy. 
STOMATA. The minute orifices or pores in 
the epidermis of the leaves of plants. Most, 
though not all, have an oval outline, or appear 
like areole, with each a slit in its centre; but 
the edges seem like a sort of thickened sphinc- 
ters capable of opening and shutting, and the slits 
vary in both size and form. ‘They usually occur 
on the under surface of leaves which are freely 
exposed on all sides to the air, and on the upper 
surface of leaves which float on water; and they 
perform very important functions in the general 
economy of vegetable life and growth. See the 
article ABSORPTION IN PLANTS. 
STONE. A piece of rock. When water-worn 
and small, it is a pebble; when water-worn 
and large, it is a boulder; when scarce, small, 
and beautiful, it is a gem; when cubical, com- 
pact, quarried and cut for building or for sculp- 
ture, it is a block; when stratified and fashioned 
into a slab for a floor or a foot-path, it is a pav- 
ing-stone; and when laminated and split and 
dressed for roofing, it isa slate. A mass of peb- 
bles, from the size of a pea to that of a small 
potato, constitutes gravel; a deposit of this with 
intermixtures of sand and organic remains con- 
stitutes gravelly soil; and any kind of diluvium 
or alluvium, containing either loose or landfast 
boulders or a considerable proportion of large 
pebbles, constitutes stony soil. See the article 
GRAVEL. 
“Tt has been argued, and is not yet determined,” 
said a distinguished agricultural writer of eighty 
years ago, “ whether stones are hurtful or bene- 
ficial to arable lands. Examples are not wanting 
on both sides of the question ; though in general, 
it seems rather to be carried for them. How- 
ever, nothing can excuse leaving a stone in any 
ground so large as to interrupt the plough. If 
they are very large, they should be blown to 
pieces with gunpowder, and then be carried off. 
Some spots very fertile in several kinds of grain 
seem to consist of nothing but stones; and in- 
