154 ABSTRACTS AND REPORT.

DOES INVASION OF THE SPLEEN, LIVER, AND LYM­PHATIC GLANDS OF THE MUSCLES BY BACTERIA ALWAYS TAKE PLACE BY WAY OF THE BLOOD­STREAM?

As suggested by the author, the form of this question might be, Is "generali­sation " always correctly explained?

It is generally held that bacterial invasion of the spleen, liver, and body lymphatic glands takes place by way of the blood-stream, and that such infection can take place in this way only. Innumerable experiments have shown that bacteria are arrested in these organs when they are introduced into the blood, and the view tbat bacteria can only reach these organs by way of the blood has to a certain extent come to be accepted as a fact. This view is of special importance in connection with tuberculosis from the point of view of meat inspection, in which generalisation is a matter of great moment.

The author proceeds to deal at some length with tbe views expressed upon this subject by a number of authorities-Johne, Ostertag, and others.

The escape of tubercle bacilli into the blood-stream results in the generali­sation of the disease. Fortunately both in man and in animals the disease progresses but slowly towards generalisation, and the explanation of the mild­ness of many cases of tuberculosis lies in the fact that the infection is slight and the process comes to a stop before invasion of the blood has taken place. There is the danger that when the disease has been arrested for a long time it may become active again and lead to generalisation.

Intravenous inoculation imitates the process from the actual moment of generalisation only, but entirely leaves out of consideration the physiological course of the infection from the very outset up to the time that generali­sation occurs. The key to the explanation of many cases of tuberculosis lies in this fact.

The frequently observed tuberculosis of the retro-pharyngeal and mesen­teric glands in naturally infected animals shows that the disease commences \\ith the entrance of ingested bacilli into the lymphatic system. The author then asks the questions: How does the disease extend? How are the spleen, liver, and glands of the muscles infected? Experiments which leave out of consideration the physiological methods of infection have only the blood-stream as the explanation.

The author has made a special study of the mechanism of infection, and especially the manner in which infection takes place when bacteria are ingested.

His experiments were in the first instance concerned with bacteria of the meat-poisoning group. The fact that these experiments gave a completely new and clear insight into the nature of physiological infection justified the supposition that the same held good for the tubercle bacillus, for no experi­mental observations have been made with the idea of ascertaining how tnbercle bacilli reach the spleen, liver, and glands of the muscles, taking the physiological aspect of the problem into consideration.

The explanation of the mechanism is of the utmost importance. If experimental evidence is forthcoming that one kind of bacterium can

reach these organs without invading the blood-stream, the same must also be possible for tbe tubercle bacillus, since the physiological possibility of it has been proved. Theories based upon experiments can only be considered as satisfactory when they take into account the facts experimentally obtained under physiological conditions.

ABSTRACTS AND REPORT. ISS

The author gives brief tabulated results of a series of experiments carried out simultaneously with the same material for each lot of animals. The classification of the facts with regard to the stage of the infection, and regarding as many organs as possible, throws full light upon the nature and manner of the infection.

The animals in the first series were fed with a weak emulsion of a strain of the bacillus paraenteriditis which was rapidly losing its virulence. The same strain caused a generalised, fatal infection seven days after the ingestion of a large dose.

The animals of the second series were fed for two days with meat that had been infected post-mortem with G~rtner's bacillus enteriditis (St. Johann strain). At the time when the experiments were made this strain was seven months old, and was losing virulence. Blood for examination was taken in every case from the heart, and the muscle chosen for examination was the quadriceps.

In the first series of experiments neither the blood nor the muscle were invaded, although the lymphatic glands, and especially those of the muscles, were involved to a pronounced extent In this case the infective material from the alimentary tract must have reached the glands by way of the lymph­stream, since neither the blood nor the muscles were infected.

The second series of animals gave an exactly analogous result. The glands, liver, and spleen were found to be infected upon the seventh day, while the blood and muscles were not infected till the twenty-third day. This leads one to conclude that the lymphatic glands were infected directly from the lymph-stream without any blood invasion, and that the muscles became infected only after the organisms had invaded the blood. This does not deny that glands may become infected in the centripetal direction in a case of generalised infection.

If tuberculosis is very advanced the muscular tissue can be shown to be infective. In cases in which only the lymphatic glands are involved and the muscle is not infective the indication appears to be that in all probability the infection must have come directly by the lymph-stream. This explana­tion makes it unnecessary to suppose that generalisation has taken place or that muscular tissue possesses any immunity, and muscular contraction and vis a tergo need not come into consideration. The explanation of the presence of organisms in the glands while they are absent from the muscles is to be found in the physiological course of the disease, which, as a rule, first involves the lymphatic system.

The infection of the glands directly from the lymph-stream may take place during the lymphatic stage of the disease. That there is a lymphatic stage of the disease was first shown by Bartel. The experiments of Reichenbach and Bock support the view that tuberculous infection depends upon the slow penetration of individual bacilli, which for the most part invade the mesen­teric glands, and thence gradually spread by way of the lymph paths. A pre­existing generalisation by way of the blood is not absolutely necessary for the infection of the body lymphatic glands. On the other hand, the author's observations show that invasion of the muscles invariably takes place by way of the blood. He has never been able to find retrograde infection of the muscles from the lymphatic glands. This agrees with the fact that even when the glands belonging to them are diseased the muscles are free from tubercle bacilli, provided, of course, there is no generalisation.

Reference to the tables given by the author reveals the remarkable fact that both spleen and liver may be infected while no organisms are present in the blood. The only possible explanation of this is that these organs can be infected through the lymph-stream, and it must be concluded that infection of these organs does not in itself indicate generalisation. The author did

ABSTRACTS AND REPORT.

not take into consideration infection of the lungs, because infection by way of the trachea and bronchi could not be excluded.

The lymphatic vessels originating in the capsule of the spleen and in the posterior surface of the liver discharge themselves into the intestinal lymphatic plexus, and the lymphatic and chyliferous vessels of the intestine which convey the infection from the intestine in the first instance drain the same area. Whether the infection follows this path may be left undecided, as may also the p05sibilityof infection of the precrural glands from the lumbar plexus.

Extension of the infective processes from the lymphatic system to the blood-stream leads to generalisation. As a result of this the muscles, the secretions and excretions, and organs already infected via the ilymph may become involved. Infection of the bones may be attributed to the lymphatic stage of the disease, in view of the close physiological connection between the lymphatic, splenic, and spinal systems.

In this way the forms of tuberculosis seen in pigs and young beasts may be explained without taking generalisation into consideration. The rarity of renal lesions in young animals, apart from fcetal infections, is also thus explained. If the disease in the lymphatic system does not come to a stop there is eventually extension to the blood-stream. This causes embolic tuber­culosis of the kidneys and the infection of the muscles, conditions seen in older animals having lesions that have been in existence for some time. The autqor does not deny the possibility of tubercle bacilli passing directly out of the intestine into the blood. Direct infection of the blood from the lymph system is contra-indicated by the slowly progressive nature of the disease. The direct passage of bacilli from the intestine into the blood is not covered by Weigert's conception of generalisation.

A proper grasp of the mechanism of tuberculous infection from the lym­phatic system considerably facilitates the examination of the carcases of animals that have tuberculous glands but the muscular tissue of which is free from bacilli. Of course there will often be conflict from the pathogenetic point of view.

By the term generalisation should be understood the escape of bacilli from a pre-existing lesion into the blood. Since lesions may be present in the liver, spleen, and glands without there being any invasion of the blood, these lesions are not a priori evidence of generalisation.

The author admits that the explanation of the mechanism of infection by way of the blood-stream has much to be said for it, and all the more since the infection of such organs as the spleen and body lymphatic glands by way of the blood is more in agreement with the usual anatomical and physiological conceptions. View:> regarding the actual course of bacterial infection must, however, be based upon the experimentally ascertained facts and not upon feasible suggestions. The author relies (or support of his views upon in­vestigations carried out upon 300 animals, and on the examination of about 6000 organs, which he made in company with Zingle.

The results of these experiments showed that the mechanism of infection is by no means always in agreement with the customarily accepted views. Only bacteria of very high virulence are able to infect directly by way of the blood-stream. If the infection is slow and the virulence lower, infection takes place by way of the lymph-stream. The blood may subsequently become infected from the lymphatic system.

How it comes about that the infection involves the lymphatic system and not the general circulation cannot be explained on physiological and ana­tomical grounds, but the fact is experimentally demonstrable, and must be considered.

If the view that infection of these organs is caused by a blood infection

ABSTRACTS AND REPORT. 157

that is not demonstrable be held, owing to the difficulty associated with explaining infection on lJhysiological and anatomical grounds, such a blood invasion is of no moment. Such an infection could not be considered as generalisation in the sense of the term as used by Weigert, for by it he indicated the final stage of the disease. The author has found remarkable pronounced lesions in the early stages on a number of occasions. Meat inspection as a practically applied science can only rest upon demonstrable facts.

If, then, the muscle as a rule proves free from organisms while the glands are diseased, and if it can be experimentally shown that infection of the glands is possible without the organism being demonstrable in the blood, these facts must be taken into consideration. (Muller, Zeitscltr. f Fleisch-u.­Milchhy., Vol. XXI!., No .. 4, January 1912, p. 106.)

HEPATIC BLASTOMYCOSIS OF THE GOOSE.

THE term blastomycosis is applied to diseased conditions caused by the multiplication in the solid tissues or in the serous cavities of blasto­mycetes-organisms which are closely related to the yeasts. In the lesions the parasites occur in the form of round or oval cells, which for the most part are discrete. They multiply by a process of budding. Cultivation of qrganisms of this type is easy, and under certain conditions, which are still imlJerfectly known for a number of them, there appear in the cultures certain forms whIch contain a variable number of spores (two to four).

A number of diseased conditions have been met with both in man and in the domesticated animals caused by the blastomycetes. The presence of organisms of this type has been observed in malignant tumours,and some author~ have suggested that they playa part in the causation of cancer.

The authors have discovered blastomycetes on two separate occasions in tatty livers of geese, where they were responsible for somewhat curious lesions.

The livers were obtained from geese that were fat and had been killed at the termination of the period of cramming. Only some fragments of the organ were available for examination, one of which weighed 375 grammes. The lesions were similar in the two cases.

Around the edge of the liver there were fifteen to twenty sacs, varying in size from a small cherry to a nut, and connected with each other by narrow channels. The sacs were sessile, and had large areas of attachment to Glisson's capsule. They did not penetrate into the parenchyma of the liver. The sacs were yellowish-white in colour and fluctuating, and they presented an appearance like a chain of echinococcus cysts along the edge of the liver.

On incision a thick, yellowish-white gelatinous material escaped, and on standing was soon cO:1Verted into a-pus-like liquid. The capsule of the liver was found to be continuous with the walls of the sacs and thickened.

Microscopic examination of the liquid showed that it contained large numbers of small cyst-like structures, which enclosed enormous numbers of the parasites. The organisms were round or oval in shape, discrete or collected into masses embedded in a gelatinous matrix. The parasites were refractile, and provided with a distinct membrane enclosing a nucleated protoplasmic mass. A large number were. observed to be budding, Qne or more little rounded bodies being visible at one or other po'e. The parasites varied in size from 1'5 to 3 microns in diameter.

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