Robert von Ostertag.

Handbook of meat inspection online

. (page 35 of 87)
Online LibraryRobert von OstertagHandbook of meat inspection → online text (page 35 of 87)
Font size
QR-code for this ebook


On the other hand, Kiinnemann, in accord with Olt, found that
nematodes are occasionally present in the tubercles.

For the microscopic differential diagnosis of entozoic and
glanderous tubercles in the lungs of horses, see under " Glanders.'*

Finally, attention should be called to other alterations which
are caused by certain processes during the act of slaughter or dur-
ing the death struggle ; viz., aspirations of stomach contents and
so-called blood aspiration.

ASPIRATION OF THE STOMACH CONTENTS. During the act of
slaughter, the contents of the stomach may pass into the pharynx
and thence by violent inspiration may be drawn into the trachea
and bronchi.

Aspiration of tlte stomach contents is most frequently observed
in the lungs of cattle. This fact depends upon the peculiar position
and character of the esophagus, in consequence of which the stom-
ach contents of recumbent animals must from mechanical reasons
pass into the esophagus. The regurgitation of the stomach contents
into the Esophagus is increased by trampling upon the abdomen, as
is practiced by butchers in accelerating the flow of blood.

In slaughtering by the Jewish method, the stomach contents
flow directly from the esophagus into the trachea, since both organs



RESPIRATORY APPARATUS 331

are severed simultaneously. A portion of tlie stomach contents is
therefore almost always found mixed with blood in the lungs of
animals slaughtered in this manner. This result is brought about
partly by the fact that after the throat is cut the inspirations per-
sist for some time with undiminished force. The material which
flows into the trachea is violently drawn into the ramifications of
the trachea and may be so firmly wedged in the bronchial tubes that
it can not be driven out again by expiration. The aspirated stom-
ach contents may thus lead to agonal emphysema, in consequence
of the obstruction of the air passages.

Recognition. Aspiration of the stomach contents may be easily
recognized by making a cross section of the lungs below the bifur-
cation of the trachea.

Judgment. Lungs containing aspirated stomach contents are
highly unfit for food and are to be excluded from sale if the abnor-.
mal contents are not confined simply to the trachea and larger
bronchial tubes, so that the foreign material may be entirely
removed by cutting open these tubes.

On account of the frequency of the occurrence of aspirated
stomach contents in bovine bronchi, meat dealers, by means of
knobbed scissors, commonly open and clean these structures in the
preparation of the lungs.

ASPIRATION OF BLOOD. So-called blood aspiration in the lungs
occurs during slaughter in cases where the trachea and the blood
vessels of the neck are severed. The blood may thus be drawn into
the finest bronchial ramifications as long as the animal continues to
breathe.

Blood aspiration is observed most frequently in cattle and hogs
killed by the Jewish method. To be sure, the latter animals are
stunned before sticking and inspiration during bleeding is therefore
less frequent. Nevertheless, as shown by W. Eber, a phenomenon
analogous to blood aspiration is frequently observed in hogs,. but
this depends on the peculiar method of bleeding hogs. The blood
of hogs is a valuable material ; so valuable, indeed, that the blood
of cattle is falsely substituted and sold as hog blood. The blood
of hogs, therefore, is carefully collected and the butcher closes the
wound in the skin in order to prevent the loss of the blood when
the vessel utilized for receiving it becomes fall. By thus pressing
the lips of the wound together the blood which flows from the sev-
ered cervical vessels is forced toward the point of least resistance
being in this case the partly severed trachea and may thus pass



332 NOTEWORTHY ORGANIC DISEASES

into the trachea and bronchi merely from gravity and without assist-
ance from respiratory movements. The blood does not flow out
again from the trachea, since the inter-annular bands are injured in
cutting in such a manner that they open only inward, like valves.

Recognition. The aspiration of blood in cattle and the analo-
gous phenomenon in hogs are characterized by the appearance of
red-colored lobuli scattered everywhere throughout the pulmonary
tissue ; but, as a rule, in such a manner that they are separated
from one another by portions of the lung of a normal color. In
this way blood aspiration is distinguished from hypostasis. Blood
aspiration is easily distinguished from lobular pneumonia by the
fact that in the former the red-colored lobuli do not project beyond
the surface of the lung, and feel, not like hepatized areas, but almost
like normal pulmonary tissue ; and, finally, by the fact that upon
section the bronchi and bronchioles appear to be filled with coagu-
lated or non-coagulated blood, while the pulmonary tissue itself is
still filled with air (presence of foam in stroking the cut surface).
"W. Eber found that in blood aspiration the blood in the lungs
undergoes partial resorption. In aspiration of blood, a red colora-
tion of the cortical zones of the bronchial glands is frequently
observed and is due to the accumulation of resorbed red blood
corpuscles.

Judgment. In moderate aspiration of blood, the lungs are not to
be condemned, while in excessive aspiration they are to be consid-
ered as unfit for food, particularly because they decompose more
rapidly than normal lungs.

For the recognition of artificially inflated lungs, see Chap-
ter XV.

(d) Pleura.

The pleura exhibits only a few independent alterations. The
majority of these alterations depend upon abnormal conditions and
processes in the lungs. This is especially true of inflammation of
the pleura.

INFLAMMATIONS. Only three forms of primary pleuritis are
observed in food animals. One form is caused by foreign bodies
which penetrate the thoracic cavity from the stomach ; a second
form of primary pleuritis develops in consequence of fracture of
the ribs. The third form is of infectious origin and occurs only in
hogs ; it has a chronic character and is ushered in with multiple
formation of abscesses (see " Infectious Pleuro-peritonitis of Hogs ").



RESPIRATORY APPARATUS 333

A.11 oilier pleural inflammations develop secondarily in association
with pneumonia.

Primary inflammations of the pleura of food animals are, in
general, benign affections. They usually do not cause death or
forced slaughter and are thereby essentially different from similar"
peritoneal inflammations. Traumatic inflammation of the pleura as
well as that caused by fracture of the ribs without complication
heals in the majority of cases by proliferation of connective tissue
at the point of irritation after the formation of the fibrinous or sero-
fibrinous exudation. In slaughtering animals we often unexpectedly
^nd evidences of such inflammation in connective tissue capsules
and adhesions extending from the folds of the pleura. Even the
specific alterations of infectious pleuritis of hogs are, as a rule, dis-
covered unexpectedly in animals which showed no symptoms of the
disease during life.

The secondary inflammations of the pleura in pneumonia of
horses and cattle, hemorrhagic septicemia of cattle, and swine
plague, run exactly the same course as that of primary pneumonias.
It is only in case of necrosis of superficial portions of the lungs that
putrefactive and septic bacteria from the outside world may gain
entrance to the pleuritic exudation and thereby cause the complica-
tion of sapremia and septicemia. In the majority of cases the
pleuritic process heals simultaneously with the pneumonia and
leaves only such connective tissue adhesions as, for example, are so
frequently observed in hogs after recovery from swine plague. In
consequence of the connective tissue adhesions, pulmonary abscesses
which extend to the surface may be prevented from opening into
the pleural cavity and may be rendered harmless to the organism
after complete encapsulation.

The anatomical forms of pleuritis are the same as those of peri-
tonitis. Judgment on them should be governed, therefore, by the
same rules as judgment of peritonitis.

Beside inflammations, the following alterations of the pleura
deserve consideration :

HYPOSTASIS. In natural death and in slaughtering during the
crisis of disease, hypostatic congestion appears on the low-lying
parts of the pleura in the same manner as in the lungs. The red
coloration of the pleura, however, which may appear when the blood
passes into the pleural sac during bleeding, must be distinguished
from hypostasis. In the former we find small and large blood clots-
on the pleura and a diffuse red coloration of this structure.



334:



NOTEWORTHY ORGANIC DISEASES



TUMORS. In addition to sarcomata, false neuromata 01 the
Intercostal nerves (myxo-fibromata) may occur quite frequently
under the pleura of cattle. These neomorphic structures occupy a
position corresponding to the course of the intercostal nerves in the
intercostal spaces underneath the pleura. They are conspicuous,
therefore, when they occur in large numbers, for their regular
arrangement.

False neuromata of the intercostal nerves in their early stages
may be confused with tuberculosis and in their later stages with
echinococci. At first they form gray, firm tubercles varying in size
from a hemp seed to a pea and surrounding the nerve like a ring
(Fig. 81). In the large tubercles they sometimes reach the size of



Fm. 81.




False neuroma of the intercostal nerves in cattle.

a potato the myxomatous tissue is more conspicuous. In this
manner structures arise which, to the naked eye, possess great
resemblance to echinococci. Section, however, immediately demon-
strates to the inspector the true nature of the alteration, for only
a slight quantity of slime-like tissue and no fluid oozes from
the spherical or elongated structures. Myxo-fibroma of the
intercostal nerves is distinguished by the complete absence of
caseation.

False neuromata of the intercostal nerves are but rarely
observed in slaughtered cattle. Moreover, they exercise no influ-
ence over the character of the meat. It is necessary merely to
remove them and this may be done in connection with the nerve,
strands.



RESPIRATORY APPARATUS 335

INFECTIOUS GRANULATIONS. In cattle, tuberculosis of the pleura
is of unusually frequent occurrence. In hogs it is very rare. Pleural
tuberculosis of cattle begins with proliferation of small red connec-
tive tissue papillae and filaments which give the pleura a velvety
appearance. Later, casefyiug and calcifying tubercles are observed
in the larger connective tissue proliferations (Fig. 82). Pleural
tuberculosis is also characterized in the advanced stages by the
strongly developed connective tissue framework of the tubercle.
Tuberculous neomorphs on the pleura may reach a considerable
thickness (up to 20 cm. and over), and this without the subjacent
parts, ribs, and intercostal muscles showing even the slightest trace
of disease per continuifatem. This is of the greatest importance in
rendering judgment on serous tuberculosis with reference to the
neighboring musculature. Attention should again be called to the
fact that the corresponding lyinph glands
of the pleura are the retro-pleural, thoracic
and mediastinal, and -not, as has been
erroneously assumed, the lymph glands of
the anterior extremity, axiliary and pre-
scapular glands.

"We should not confuse incipient
pleural tuberculosis with proliferating in-
flammations of the pleura which develop
from friction from echinococci, and which
extend to the pleura.

Besides tuberculosis, actinomycosis

J Serous tuberculosis of cattle

may exceptionally occur on the pleura of (pearl disease).

cattle. The infection arises either from

the lung or, in pleura phrenica, from the liver. In the latter case
actinomycotic tissue penetrates the diaphragm. When all other
characters are disregarded, actinomycotic tubercles are distin-
guished by the soft, myxoma-like oozing surface on section, showing
numerous yellow granules, as well as by the strongly developed
neomorphs of connective tissue in the neighborhood of all other
similar alterations.

In chickens and pheasants, the air sac mite (Cytodites nudus)
is frequently found in the air sacs of the thorax, neck and abdomen.
The mites are visible to the naked eye as yellowish or brownish
points. They may cause inflammatory alterations of the membranes
of the air sacs in the form of yellow gelatinous effusions or mem-
branous deposits (Kitt). In cases of extensive invasion of the lungs
and trachea, death may result from inflammation of these air pas-




336 NOTEWORTHY ORGANIC DISEASES

sages and from asphyxiation (Gerlach, Zschokke, Megnin). Holzen-
dorff also found the mites in miliary abscesses of the liver, lungs
and kidneys of chickens.

PARASITES are only occasionally found in the sub-pleural tissue.
In one instance the author found under the pleura of a hog an
Ecliinococcus multilocularis which presented the appearance of




a, Echinococcus under the costal pleura in a hog.

tuberculosis (Fig. 83). A similar case was recently observed by
Benedictis in cattle. The dangerous cysticercus of cattle and hogs
has a special predilection for the intercostal muscles which are
covered by the pleura.



5. Circulatory Apparatus.
(a) Heart.

In the heart the following parts require special discussion : The
epicardum with the pericardum ; the inner lining of the heart (endo-
cardium) ; the cardiac muscle (myocardium).

Epicardium and Pericardium.

HEMORRHAGES. The epicardium is frequently the seat of
petechisB which appear as sympathetic symptoms of toxic, infectious,
general diseases under the serous membranes. For example, in
anthrax, Texas fever, and fowl cholera, the epicardium shows black



CIRCULATORY APPARATUS 337

spots or petechise in an almost pathognomonie manner. Large
quantities of blood are found in the pericardial cavity in rupture of
the heart, or of the coronary artery.

INFLAMMATIONS of the pericardium arise primarily from wounds.
Furthermore, they may develop secondarily under the same condi-
tions which cause secondary pleuritis. In the latter case, the
inflammation of the pericardium represents merely a complication
of primary pulmonary inflammations. Traumatic pericarditis is a
typical disease of cattle. It will be discussed in greater detail
under " Sapremia." It should be noted that occasionally in hogs a
serous or sero-fibrinous pericarditis is observed as the only phe-
nomenon of swine plague. More frequently, however, a simultane-
ous inflammation of the pleura and lungs is observed.

Connective tissue proliferations of the epicardium and of the
inner layer of the pericardium, sometimes leading to adhesions of
these parts, are observed after recovery from acute pericarditis.
This condition is most frequently observed in hogs after swine
plague and in cattle after recovery from traumatic pericarditis.

Connective tissue adhesions between the epicardium and the
inner layer of the pericardium interfere with a careful inspection of
the surface of the heart, especially for cysticerci. In inspecting the
heart, it is therefore desirable to remove the pathologically altered
epicardium with a knife.

TUMORS. Tumors may project into the pericardial cavity either
from the pericardium or from the epicardium. According to Kitt,
fibromata and fibro-sarcomata occur most frequently.

INFECTIOUS GRANULATIONS. Among the specific neomorphic
formations, tuberculosis of the pericardium is of frequent occurrence
in cattle. The pericardium as well as the pleura and peritoneum
may apparently be affected with primary tuberculosis. Ordinarily,
however, tuberculosis of the pericardium is associated with pul-
monary and pleural tuberculosis.

When the epicardium is affected, it is a striking fact which is
sufficiently explained by the centripetal course of the lymphatic
vessels that even the most serious cases of epicardial tuberculosis
begin with complete integrity of the myocardium.

Endocardium.

The inner lining of the heart may exhibit petechise under the
already frequently noted conditions, and also insignificant cloudiness



338



NOTEWORTHY ORGANIC DISEASES



in consequence of partial fatty metamorphosis or proliferating inflam-
mation.

According to Glage, cysts varying in size from a pea to a bean
and resembling cysticerci occur quite frequently on the auriculo-
ventricular valves in hogs. Gibson also observed similar cysts in
sheep.

For the differential diagnosis of endocardial petechise, attention
should again be called in this connection to the systolic hyperemic
conditions of the myocardium and to the valvular hemorrhages iu
fasting calves (compare page 174).



FIG. 84.



INFLAMMATIONS. Inflammations of the duplicatures of the endo-
cardium or the so-called car-
diac valves are not without
importance for meat inspec-
tion. Two forms are distin-
guished: Verrucose and ulcer-
ous valvular endocarditis.
Verrucose valvular endocar-
ditis may reach such a con-
dition that the death of the
animal is brought about by
mechanical obstruction of the
circulation. Furthermore,
thrombi may be formed upon
the greatly thickened cardiac
valve so as to exercise the
same influence upon them as
strong connective tissue pro-
liferations upon the valvular
apparatus. With regard to
the etiology of the verrucose
form of valvular inflamma-
tion, it may represent a

simple proliferating inflammation or an infectious process. Cocci
and bacilli have been found in the proliferating valves. A special
and frequent form of infectious verrucose valvular endocarditis is
caused by the bacillus of swine erysipelas (Fig. 84).

Ulcerous or diphtheritic valvular endocarditis begins with a
desquamation of the superficial layers of the cardiac valves. Later
the desquamating areas are modified into ulcers. Large thrombi
arise in the ulcerous spots (Fig. 85). The loosening of the thrombi




Heart of a hog with valvular verrucose endo-
carditis as a sequela of swine erysipelas.
a, warty thickenings.



CIRCULATORY APPARATUS



339



may give rise to hemorrhagic infarcts in the liver, lungs, spleen and
ludneys.

Ulcerous inflammation of the cardiac valves is either of toxic or
infectious origin. In the latter case pyogenic organisms are of special
importance. For this reason ulcerous valvular endocarditis may
serve as a starting point in pyemic processes (see under " Pyemia ").

FIG. 85.




Beef heart with valvular ulcerous endocarditis, a, cut surface of the thrombus on
the ulcerous cardiac valve; b, base of the thrombus after artificial separation
from the substratum* c, ulcerous part of the cardiac valve.



TUMORS. Tumors of the character of fibromata and fibro-
sarcomata may arise upon the endocardium as well as on the peri-
cardium and epicardium. According to Kitt, the tumors take their
origin from the sub-endocardial tissues, are commonly pedunculate,
and connected with a trabecula, papillary muscle, or tendon. Tumors
which project into the cardiac cavity may reach the size of the fist*



340



NOTEWORTHY ORGANIC DISEASES



Myocardium.

DISSOLUTIONS OF CONTINUITY in the myocardium cause deaths
They are produced by injuries from the outside (stabs and shot
wounds) and by spontaneous rupture. Spontaneous rupture is
observed as a sequela of fatty metamorphosis of or infestation of
the myocardium with parasites (echinococci). In old horses,,
atheromatosis of the auricles sometimes leads to rupture of the*
heart. Death occurs from hemorrhage into the pericardium.



FIG. 87.



FIG. 86.




Incipient fatty metamor-
phosis of the cardiac
muscle.




Heart of a hog infected with Cysticercus
cellulosaei.



DEGENERATIONS. The most important alterations of the myo-
cardium are cloudy swelling and fatty metamorphosis (grayish-re^
or grayish-yellow discoloration, cloudy and soft, friable consistency).
Both forms of degeneration arise under the same conditions as-
those of the liver and kidneys.

CIRCULATORY DISTURBANCES AND INFLAMMATIONS. Embolic in-
farcts are observed in the myocardium in malignant foot and mouth
disease of cattle (Johne). Miiller observed a case of the formation
of multiple abscess in the myocardium of a cow which, one year?



CIRCULATORY APPARATUS 341

previously, suffered from an acute attack of foot-and-mouth disease.
Metastatic abscesses may develop in the myocardium in association
with other processes which are ushered in with suppuration. This
is quite frequent in cases of metritis and is occasionally observed
also in consequence of contagious coryza and suppurative ompha-
lophlebitis (Kitt). The abscesses may also arise from necrotic foci
in the myocardium which are due to embolic transportation of the
necrosis bacilli (Bang and the author).

INFECTIOUS GRANULATIONS. In rare cases tuberculosis of the
myocardium develops in food animals. In the few cases which
have been seen by the author, the tuberculous areas exhibited the
^characteristic form of hemorrhagic infarcts.

PARASITES. In the myocardium there is frequently observed
injurious cysticerci, especially C. bovis in cattle and C. celluloscv in
hogs and sheep. The parasites show a predilection for a position,
under the epicardium and endocardium. They may, however, pene-
trate the whole musculature of the heart. Furthermore, echino-
cocci are occasionally met with in the myocardium. They may
occasion sudden death by rupture of the connective tissue capsule
and the escape of the encysted worms into the ventricles. Large
echinococci, however, may, in and of themselves, and without rap-
ture of their capsules, produce threatening symptoms and sudden
death from cardiac paralysis, especially when they have their seat
in the septum of the heart.

(b) Blood Vessels.

As a noteworthy local disease of the blood vessels, attention
should be called to verminous aneurisms of the branches of the
abdominal aorta, especially of the trunk of the anterior mesenteria
artery in the horse. This verminous aneurism, which, as is well
known, is caused by Strongylusarmatw, may reach quite considerable
proportions without causing any disturbances in the health of the
horse. Occasionally a fatal hemorrhage is observed in consequence
of the rupture of the wall of the aneurism.

Calcification is sometimes observed in the aorta of cattle. The
intima of the vessel, which is distinguished by its inflexibility, is
permeated with cloudy-white, sharply-delimited, leaf-shaped deposits
of lime, the middle portion of which is concave. Rough, sand-like
deposits may exist at the same time (Kitt). For purulent inflamma-
tions of the walls of tho blood vessels, see under " Pyemia."



342 NOTEWORTHY ORGANIC DISEASES



6. Lymphatic Glands.

The lymphatic glands have an important physiological role..
They act as a filtering apparatus and thereby purify the lympk
stream from admixtures of foreign substances before it passes into
the blood circulation. The larger corpuscular elements are cer-
tainly filtered out of the lymph. The filter is likewise effective
even for bacteria, in different degrees in different animals. Thus,
in cattle and hogs the lymph glands may for a long time restrict a
tubercular process to the point of origin and prevent an infection
of the blood. Pyogenic bacteria are also prevented from entering
the blood circulation by the lymph glands of food animals. In the
smaller animals for instance, in the experimental animals of the
laboratory this protective function is much less effectively per-
formed.

INFLAMMATIONS. The lymph glands react very readily to irrita-
tion. They are therefore regularly inflamed when inflammatory
processes occur in their tributary area. In ordinary inflammatory*
swelling, the lymphatic glands are enlarged and on cross section
more fluid exudes. In more advanced stages of lymphadenitis,
hemorrhages into the tissue of the lymphatic glands are associated
with the original process (hemorrhagic lymphadenitis).

A swelling of all the lymphatic glands is observed in acute
infectious diseases and in chronic ' diseases which have become
acute ; for example, in sepsis, pyemia, and chronic tuberculosis after
the entrance of the tubercle bacilli into the blood.

Inflammations of the lymphatic glands usually disappear as
rapidly as they arise. Yellow-colored spots may remain as evidence
of the hemorrhages which sometimes accompany inflammations.

SPECIFIC ALTERATIONS. In contrast with simple adenitis as a
sequela of ordinary inflammatory processes, all inflammations of



Online LibraryRobert von OstertagHandbook of meat inspection → online text (page 35 of 87)