i. Softening.
k. Adventitious products.
The preceding distribution of the morbid
conditions of the air passages may be advan-
tageously methodised under two heads : first,
those of the bronchi (as defined in the account
of their normal anatomy) ; secondly, those of
the lungs.
The bronchi are liable to several forms of
inflammation :
a. Acute bronchitis.
b. Chronic bronchitis.
c. Plastic bronchitis.
Collapse of the lungs should be considered,
pathologically, as rightly ranking under the
denomination of the diseases of the bronchi.
The various forms of asthma, and hooping
cough, belong to this species.*
The bronchi are subject to two forms of
dilatation. In the first, a tube is uniformly
dilated at every part of its circumference. In
the second, the dilatation is saccular. The
* For an account of the morbid statis of the
larynx, and upper part of the trachea, see Art.
Larynx.
small bronchi and those near the surfaces and
borders of the lungs are most liable to suffer
this change. The walls of the tubes at the
dilatations are hypertrophied and thickened.
Sometimes, with the saccular variety, the
same parts are relaxed and attenuated.
The bronchitic collapse of the lungs occurs
under two distinct aspects, the diffused form,
and the limited or lobular form. Of these
the latter variety is the more striking or cha-
racteristic, and has been, especially in the
lungs of children, the subject of more discus-
sion than the former. But the diffused form
is by far the more common, and is of frequent
occurrence in its slighter degrees. In both
conditions the pulmonary tissue presents a
dark violet colour as seen beneath the pleura ;
internally it is red.
In considering the causes which tend to
produce this condition they seem to resolve
themselves into the following: 1st. the exist-
ence of mucus in the bronchi, which is more
liable to produce obstruction according as it
is more thick and viscid ; and 2ndly, weakness
or inefficiency of the respiratory power; Srdiy
inability to cough and expectorate. Of
these conditions, the first must be considered
as the exciting cause, the others as predis-
posing, co-operating with the first, but in-
capable, without it, of producing collapse.*
With bronchitic collapse of the lung is
almost always associated emphysema of the
unaffected portions of the same lung(Gairdner).
Inflammation of the mucous membrane of the
bronchi produces changes which are denoted
by redness and tumidity of the tissue, a
secretion of muco-serum, purulent mucus, or
pus, according to the stage and intensity of
the inflammation.
This latter is the condition of superficial
suppuration. The swelling of the mucous
membrane and sub-mucous tissue, which as-
sumes the form of watery infiltration into the
* For a full discussion of this interesting subject,
see " Pathological Anatomy of Bronchitis, and the
Diseases of the Lung connected with Bronchial Ob-
struction." By W. T. Gairdner, Edin. 1850. Md-
moire sur une Distinction nouvelle de deux Formes
de la Bronchite ; precede' de quelques considerations
generales sur I'lnflammation de la membrane mu-
quese des voies-aeriennes. Par J. H. S. Beau.
Archives Generales de la Medicine, Sept. et Oct.
1818. Memoire sur quelques Parties de PHistoire
de la Bronchite et de la Broncho-pneumonie chez
les Enfants. (Archives Ge'nerales, Oct. 1851, et
suivantes.) Memoire sur la Broncho-pneumonie
Vesiculaire chez les Enfants. (ReVue Me'dico-
Chirurgicale de Paris, 1852. Par les Drs. Barthez
et Rilliet.) Traite Pratique des Maladies des
Nouveaux-Nes, &c. Paris, 1852. Par M. Bonchut.
A Memoir by Legendre and Bailly, in the Archives
Ge'ne'rales de Medicin, on the " e'tat foetal " of the
lungs, torn. Ixiv. On the Diseases of the Organs of
Circulation and Respiration, Art. Atelectasis. By
Hasse. Sydenham Society. Die Bronchio-pneu-
monie der Neu-gebornen und Sauglinge. Berlin,
1837. By Seifert. Medico- chirurgical Trans., for
1830. By Dr. Alderson. Der Mechanismus der Re-
spiration und Circulation. By Mendelssohn. Beitrage
zur Experimentellen Pathologic und Physiologic.
By M. Traube. Die Bronchitis der Kinder.' Leipzig,
1819. Dr. Fuchs. Diseases of Infancy and Child-
hood. West.
RESPIRATION.
293
areolar tissue, being accumulated at individual
spots, is important and worthy of great atten-
tion, on account of the facility with which it
interferes with the calibre of the tubes,
Chronic inflammation of the bronchial mem-
brane gives rise, especially in parts abounding
in glands, to glandular hypertrophy, mucous
polypi, epithelial growths, spongy and velvety
thickening, relaxation of the muscular and
fibrous elements, fol lie ular ulceration, c.
The pathological conditions of the broncho-
pulmonury mucous membrane differ in no
respect from those of any other membrane of
this class.
In plastic or exudative bronchitis are cha-
racterised by a morbid action of a croupous
nature.
In bronchial croup the tubular exudations
from the larger bronchi present a calibre in-
versely proportional to their thickness, and
those thrown off from the finer ramifications
occur as solid cylinders.
Asthmatic affections may either have their
exciting cause in the lungs or in the condition
of some remote organ. They partake of a
nervous and muscular character, and are
frequently caused by a collapse of a portion
of the lung. The collapsed part operates as
an excitor of the muscular spasm.
English pathologists recognise the follow-
ing forms of disease proper to the parenchyma
of the lungs: Pneumonia, or inflammation
of the cell-tissue of the organ ; gangrene ;
/KEinorrhage ; oedema ; emphysema ; phthisis ;
cancer.
Inflammation of the vesicular tissue of the
lungs is marked by the exudation of the co-
loured elements of the blood. This fact was
once supposed to prove the absence of epi-
thelium in the air-cells. This inference is
erroneous.
Inflammation of the lung is divided into
three stages, according to the consistency or
physical condition of the exuded product.
The first is that of engorgement ; the second
is that of hepalisation j the third is that of
grei/ hepatisation.
Gangrene of the lungs occurs under two
anatomical forms, the diffused and the cir-
cumscribed.
Cancer of the lung, most commonly of the
encephaloid species, occurs in the forms of
secondary nodules and primary infiltration,
accompanied or not by tuberous formation
on either mediastinum about the main right
bronchus (Walsh).
The anatomical changes which occur in the
lungs in phthisis are referrible to three main
stages, corresponding habitually to certain
varieties in the symptoms, and always to
modifications in the physical signs. The
first stage is that of deposition and induration;
the second that of softening; the third that
of excavation.
The exact scat of pulmonary tubercle has
proved, from the dawn of pathology to the
present time, a controverted point. The
question is whether the deposit of the morbid
product occurs first on the free surface of the
air-vessels into the substance of their walls,
or between them into a supposed inter-
vesicular tissue. From Morton and Bayle
to Rokitansky and Lebert, advocates for each
of these " seats of election" have contended
in turn. The free or aerial surface of the
air-cells is now the commonly accepted si-
tuation of the tuberculous deposit.
The nature of the tuberculous matter is
not less disputed ; witness the following defi-
nitions :
Tubercle is a specific exudation (Ancell).
Tubercle is a degraded condition of the
nutritive material (Dr. C. J. B. Williams).
Tubercle is composed of the products of
inflammation (Reinhardt).
Tubercle is composed of the dead-tissue
elements (Flenle).
Tubercles themselves consist of abnormal
epithelial cells (Dr. W. Addison).
Tubercles are composed of metamorphosed
organised elements; a metamorphosis co-
ordinate with the fatty and the waxy de-
generations (Virchow).
Tubercle is a product secreted from the
blood by the epithelium lining the air-cells
(Schroeder Van der Kolk*).
The mechanism of emphysema is still sub
judicc. Some authors, with Laennec, ex-
plain it on the supposition that the walls of
the air-vesicles yield under the force of the
air when the expiratory current is impeded.
Another class of writers attribute it to an
excess in the inspiratory force. Mr. Rainey
contends that the parietes of the air-cells
suffer a change of structure by fatty dege-
neration,, and that this change stands to em-
physema in the relation of a causal condition.
Dr. Gairdner affirms that emphysema of one
portion of the lung cannot occur unless a
col/apse has happened in another part. Em-
physema fills up pneumatically the space lost
by the collapse, and no more. The chest
ean only be filled; it cannot be inflated
beyond a given inspiratory limit. The air-
passages of the emphysematous portions are
free, not obstructed. If already the cavity
of the thorax be uniformly filled, it is certain
that emphysema is rendered physically im-
possible. Emphysema is plenum counter-
balancing collapse a vacuum.
It is yet by no means determined to what
extent, if at all, the shedding or desquamation
of the epithelium of the air-passages takes
place in disease.
( Thomas Williams.')
STOMACH AND INTESTINE.
(Syn. Stomach, formerly Maiu, Eng. ; Magcn,
Germ.; oro/udxo^, O'ao-rrjp, Gr. ; Stomachus,
Ventriculus, Lat. ; Stomaco, Ventricolo, Ital. ;
Estomac, Fr. ; Estomaco, Sp. ; Intestine or
bowel, formerly gut, tripe, cut rail, Eng.; Darm.,
* See British For. Med. Chir. Rev., for January
April, July, 1853 ; in which Nos. respectively three
excellent articles by Paget, Jenner, and Sieveking,
will be found.
u 3
294.
STOMACH AND INTESTINE.
Germ. ; evrepoz/, Or. ; Intestinum, Lat.;Inlcstino,
Ital. Sp.; Ititestin, Fr.*)
What are called the organs of the animal
body consist of a diversity of tissues, so
grouped and united with each other as to
form a more or less continuous and aggregate
mass ; the functions of these various struc-
tures being also associated in a single general
purpose, which may be regarded as the sum
of their several actions on the system at
large.
Among such groups of structures, there
is none more remarkable than that which
effectuates the series of processes collectively
termed DIGESTION. For other organs are
so far exclusively dependent on the blood,
as that many influences of the outer world
can scarcely reach them, except through
the medium of this fluid. Entrenched, as
it were, behind this the great river of ani-
mal life, they are secured from any but
the indirect action of ^ numerous physical
agents. But the organ of digestion lies out-
side this stream : and occupies a kind of
neutral territory, between life and matter,
where the various forces of both can co-
operate for its benefit, in equal and har-
monious conjunction. Or rather, let us say,
the digestive canal is the threshold of the
House of Life, where dead matter is first
endowed with those properties which enable it
to become a living constituent of the animal
body.
The group of organs before us has indeed a
special relation to the animal. For although
digestion is usually enumerated amongst
those general or organic functions which are
shared in by everything that has life, vege-
table as well as animal, still the means by
which the process is effected in these two
forms of organization, constitute as important
a distinction between them, as the mere pre-
sence or absence of other functions. So that,
the digestive cavity is, on the whole, as charac-
teristic of the animal, as the organs of loco-
motion and innervation of which it is the
exclusive possessor.
How far the so-called vegetative functions
are really alike, or even comparable to each
other, in the two kingdoms of nature, it is not
our object here to inquire. As little do we
wish to introduce, what some might perhaps
think less out of place, a detailed comparison
between the digestive functions of the plant and
animal. But as the cavity which it is our
express object to describe is all but univer-
sally present in the latter, and absent from
the former organization, it seems desirable
briefly to contrast them in this respect.
* In respect to the etymology of these names we
may conjecture as follows: The word r<rrr,e is
radical. The stomach is so called from its connection
with the mouth (>*). Maw and magen are de-
rived from its relation to food (meat). Intestine,
ivrt'ov, entrail, ventriculus, (and darm?) connote its
internal and hidden position. Bowel (botellus), and
tripe (Tg/Tv), refer to its convoluted or tortuous
form : gut (gcotan, Anglo-Saxon, to pour), to its car-
rying fluent contents.
In the animal, a highly azotized composition is
connected with, and probably essential to,
an active life; which, in its turn, implies a rapid
waste of substance. On the other hand, the
plant lives slowly, wastes little, and contains
but a small quantity of azotized material.
The food of each appears to correspond
with these requirements. That of the plant
is, in great part, inorganic ; consisting mainly
of compounds which pervade the soil that
surrounds its roots, or the air which bathes
its leaves. While that of the animal is or-
ganic : i. e. the substances which compose it
are the products of a previous organization.
The elaboration of the food repeats the
preceding contrast. The plant builds up in-
organic into organic matter; a process of
chemical synthesis, which may well be effected
with great difficulty, and by slow stages. While
the animal scarcely does more than convert one
proximate principle into another ; a meta-
morphosis which involves no change of com-
position, and the facility of which is but par-
tially counterbalanced by its requisite rapid-
ity and amount, and the delicacy of its ad-
justment.
The agents of these processes are also
susceptible of comparison. For in the vege-
table they appear to be closely connected with
various external forces, such as light and heat;
while in the animal they seem more inherent
to the organism.*
And in both, the site of the elaboration or
change in the food corresponds to those situa-
tions where the above agents are most readily
applicable: viz. in the plant, to the leaves
and other green parts of its surface; in the
animal, to a cavity in its interior. The pre-
sence of such a cavity not only permits the
less frequent application of nutritious substance
to be compensated by the ingestion of large
quantities at particular times ; but, while it
thus meets the peculiar requirements of an
animal organism, also allows of that loco-
motion which is so necessary to the mere
prehension and selection of its scarcer food.
Its subjection to volition renders ingestion a
work of rapid and powerful mechanical force,
in place of a slow physical imbibition. And
finally, the same internal situation which
directly subjects its contents to the agents of
the digestive metamorphosis, also isolates
them from all surrounding objects, besides
favouring the temperature often necessary to
the operation. f
* Traces of this contrast between the animal and
plant, during life may be found in those processes of
putrefaction and eremacausis which respectively
effect their dissolution after death.
f Hence, instead of a digestion corresponding to
that of the animal, the plant presents us with a pro-
cess in which mere reception is so predominant, that
we might almost compare it with the absorption
of the chyme and chyle into the blood. As a kind
of fanciful corollary to this, we might regard the
crust of the earth, and the atmosphere which sur-
rounds it, as forming a common stomach or recep-
tacle of food for the whole vegetable kingdom. l ( 'or
they include, or receive, detain, and give up, the che-
mical food of the plant ; in quantities Whichjthough
STOMACH AND INTESTINE.
295
The reader will, however, observe, that the is aided by a dental apparatus, in the shape
title of the following article does not announce
an essay on the process of digestion, or the
various organs which effect it; but limits itself
to two portions of the alimentary canal,
hitherto undescribed in this work. But it is
impossible to treat of the functions of the
stomach and intestine except in connection
of a hollow cylinder enclosing long teeth,
as in the genus Napula.
The Rotifera are so named from the cur-
rents produced by their prehensile cilia i
which are here limited to groups surrounding
the mouth of the animal.
Many of them have an organ of mastica-
TM ' 11 . /
with the entire process in which they take so tion. This usually consists of three pieces :
large a share. \Vhile the numerous observa- each of the two facets of a kind of anvil being
tions and researches which have been made worked upon by the rough or toothed terminal
since the appearance of the earlier article surface of a recurved jaw, the longer limb of
DIGESTION require some notice in the which receives a muscle at its extremity.
Supplement of which the present essay forms The intestinal canal generally exhibits a
apart. For these reasons the author has felt pharyngeal enlargement, which is followed
it advisable not to confine himself too strictly by a narrow "oesophagus," of varying length,
to the exact limits uhich the heading " Sto-
mach and Intestine'' might seem to imply.
Hence, though the following essay will treat
ending in a wider "intestine." In the
Gasterodela a dilatation, called a stomach, pre-
cedes the intestine. In the Rotifer vulgaris
chiefly of the above segments of the alimentary and others, an almost globular enlargement of
canal, it will also comprise a very brief account the narrow canal is so immediately followed
of whatever is at present known concerning the
w hole digestive act. Commencing by a rough
by the constricted cloaca, as to have been com-
pared to a large intestine. The organ of
sketch of the anatomy of these parts in the digestion is also often complicated by the
animal kingdom, we shall successively consider,
their structure and functions in the human
subject ; their relation to digestion and nutri-
tion ; and finally, their appearances in disease.
COMPARATIVE ANATOMY. In the Infuso-
presence of blind tubes ; which vary, not
only in number and size, but also in posi-
tion, and possibly in import. Thus they may
open, either into an uniform and narrow canal,
or into the commencement of the intestine,
ria, whose minuteness places them at the or into the presumed gastric dilatation ; or,
lowest extremity of the animal kingdom, the c ~~ "' "
organ of digestion has already attained such a
development as to form the chief basis of
their nomenclature.
One or two genera present us with a rare
finally, as in the Digltena lacustris, a set of such
tubes may occupy both of these latter situa-
tions.
The various members of the order Entozoa
are grouped together in obedience to a cla.ssi-
and exceptional condition : viz. the absence fication which is here and there arbitrary and
of all traces of digestive cavity. Such are the anomalous, but in the main both natural and
useful. It offers three chief varieties of the
digestive organ, all of which are very inte-
resting.
a. In many as in the Echlnococd
and their congeners no trace of a special
digestive cavity is present. Without mouth,
stomach, or intestine, the creature floats free
parasitic Gregarina and Opalina ; in whom,
as in some of the Entozoa, digestion and
absorption appear reduced to a simple phy-
sical process of endosmose, which carries
the nutritious substances dissolved in the
fluid medium they inhabit at once into the
mass of their corporeal juices.
The Poh/gristria possess a plurality of in the cavity of its enclosing cyst, or buries
stomachs or internal sacs ; and the relations its barbed head in the tissues of a living
of these to the intestine, together with the con- habitation; whose juices, thus brought into
dition of the latter tube, subdivide this group relation with its exterior, are applied to its
into numerous families and genera. Thus nourishment by what seems to be rather a
many are named "anenterous," because they process of endosmose than of digestion pro-
appear to be devoid of intestine. Of these the perly so called.
Monas termo which has four or five globular /3. In other genera belonging to the Cestoid
stomachs, of 5TT jL_^th of an inch in diameter, and Trematoid divisions, there is, however,
appended immediately to its mouth may be a canal, which is apparently related to digestion,
taken as the type. Others possess similar and the main features of which repetition
sacs in connection with a simple Intestine ; and ramification may be represented by the
and are chiefly distinguished by the straight, Teenia and Distoma respectively,
curved, or wavy course of this canal, or by For example, in the Tape- worm, a minute
the single or double character, and lateral or mouth opens into a slender tube, the bifurca-
terminal position, of its apertures. Most of tions of which reach the margins of the body
them devour a living prey of kindred Infuso- where this begins to assume its regular jointed
form. From hence onwards the canal might be
compared to a ladder, with rungs at the fore
and aft extremity of each joint, at the
right angles of which its longitudinal and
transverse branches unite. It is probable that
ria; prehension being often visibly effected
by cilia, the voluntary action of which
carries a current of food into the mouth, or
removes egesta by a simple reversal of the
stream. And sometimes this act of ingestion
ordinarily sufficient, are capable of being locally-
exhausted by the excessive demands of a particular
clo^s or specie*, and renewed by an artificial supply.
these canals possess valves. But whether
tney have any constant or valid terminal ori-
fices seems doubtful.
u 4
$96
STOMACH AND INTESTINE.
Many species of Distoma or Fluke may be
regarded as types of an arborescent or rami-
fied digestive tube. From a mouth which
is suctorial and sometimes visibly muscular
a canal passes backwards, to divide into two
large branches. These run along the margins
of the oval and flattened animal, giving off
other branches ; from which proceed a final
series of anastomosing twigs.
y. In many creatures closely allied to the
preceding by conformation and habits, this
ramified canal is reduced to its primary bi-
furcations, the ends of which are sometimes
slightly dilated. Occasionally there is an
enlargement, which has the situation of a pha-
rynx ; and which, in a few instances, encloses
an apparatus perhaps masticatory. In the
genus Diplostomum and others, a distinct set of
vessels, which occupies the immediate neigh-
bourhood of the intestine, has been supposed
to represent a chyliferous or vascular system.
As regards these latter forms of digestive
apparatus, it may be conjectured, that the
ramification witnessed in the Tcenia is re-
ferrible, not so much to that mere vege-
tative repetition of similar structures which
affects the whole animal, as to a merging
of the digestive in the circulatory function.
In any case, the more simple form of tube
last mentioned appears rather akin to an
advance, than to a retreat, of development ;
while it sometimes visibly coincides with the
appearance of a new system of canals, con-
nected with the circulation of a proper nu-
trient fluid.
In the Nematoid Entozoa, the alimentary
canal is generally a straight tube, which oc-
cupies the axis of the vermiform animal, and
opens at its extremities. In most genera
as in the Trichina, Tricocephalus, Ascaris,
Slrongylus, and others it widens posteri-
orly ; where it often experiences a further
dilatation, which only ceases near the anus.
Rarely, other indications of separation are
added: an oesophageal dilatation, as in the
Ascaris lumbricoides ; or an enlargement cor-
responding in position to a stomach, as in
the Linguatula and Filaria.
Rudiments of the organs accessory to di-
gestion have also been detected. Blind tubes
opening into the canal near its mouth are
found in several genera : and the position of
these has sometimes led to their being re-
garded as salivary. While rarely there is a
tube which opens into the intestine in the
situation of a biliary organ.
In the mode of attachment of their diges-
tive canal, this division of the Entozoa otfers a
marked contrast with the preceding. In the
Sterelmintha (or solid worms) the tube is