Pressure upon the descending vena cave or the left innominate vein gives rise to a hum, and on the pulmonary artery to a systolic murmur heard best at the second left interspace. But long before the ordinary signs of pressure on the vessels can be detected, we can induce pressure on the vein if the bronchial glands are enlarged. This Sign is one of the earliest indications of disease in these glands.' Thus, if the child be di rected to bend his head backwards upon his shoulders so that his face is turned upwards to the ceiling above him, a venous hum, which varies in intensity according to the size and position of the swollen glands, may be heard with the stethoscope placed upon the upper bone of the sternum. As the chin is slowly depressed again the hum becomes less distinctly audi ble, and ceases shortly before the head reaches its ordinary position. The explanation of this phenomenon appears to be that the retraction of the head tilts forward the lower end of the trachea. This carries with it the glands lying in its bifurcation, and the left innominate vein is compressed where it passes behind the first bone of the sternum. I believe this ex planation to be the correct one, for in cases of merely flat chest, where there is no reason to suspect enlargement of the glands,'the experiment fails. Nor, again, can the hum be produced in a healthy child by the thymus gland. This gland lies in front of the vein immediately behind the sternum. Enlarged bronchial glands lie behind the vessels in the bifurcation of the trachea. A swelling in front of the vessels does not appear to be able to set up pressure upon the vein when the head is bent backwards in the position described. Again, in order that the experiment should succeed, the lower end of the trachea must not be fixed, and the glands lying below its bifurcation must be movable, otherwise no hum is heard when the head is retracted. Thus a child was admitted into the East London Children's Hospital for lymphadenoma. There was dulness at the upper part of the sternum, and downwards as far as the base of the heart. In this case, to my great surprise, no venous hum could be heard. The child died, and on examination of the body, yellow, flattened, cheesy masses were found adherent to the inner side of the sternum, and others, very large and im movable, were seen filling up the interval between the bifurcations of the trachea. The lower end of the air-tube was held firmly down by the mass, consequently pressure could not be brought to bear upon the vein by bend ing of the head, as the glands, being fixed, could not be brought forwards against the vessel. The experiment may sometimes fail even in cases where the lower end of the trachea with its caseous glands is free to move, for the relative position of the glands and the vein may not correspond ; but as a rule it will succeed, and a venous hum, so induced, is, I believe, a certain sign that the glands of the mediastinum are not healthy.
The mesenteric glands are, perhaps, less commonly affected than those of the neck or the chest ; but disease in them is far from rare, although it cannot always be detected during. life. The affected glands may be sepa rate, or they may unite as in other situations into masses bound together by thickened cellular tissue. In this way a mass the size of an apple, and more or less movable may be felt on manipulation of the abdomen.
The old name for disease of the mesenteric glands was tabes mesen terica, and very serious consequences were described as resulting from the glandular enlargement. It is now known that these symptoms are due, not to the mesenteric swellings, but to the lesion of which they are the con sequence ; and that the caseous glands form a part—and often only a very insignificant part—of the disease from which the patient is suffering. Like
the lymphatic glands in other situations, those of the mesentery swell up as a result of irritation or inflammation in the parts from which the lym phatic vessels passing through them take their origin. In strumous sub jects they have the same proneness as the others to become caseous. Of themselves they form a strong argument against the tubercular theory of scrofulous glandular enlargement ; for caseation of the mesenteric glands,. unless their size be such that they press upon neighbouring parts, is in itself a by no means serious matter. In ordinary cases, where there is no accompanying lesion of the bowels, the child's nutrition is good ; his spirits and appetite are satisfactory ; his temperature is normal ; and ex cept, perhaps, for some slight pallor of face, he may show no sign of ilk health. In most cases, however, swelling of the glands, if at all considera ble, is combined with scrofulous ulceration of the bowels ; but even here the consequences are not always as serious as might be expected. Much depends upon whether or not the ulceration of the intestine is accompanied by a catarrhal condition of the mucous membrane. If this be present, there is diarrhoea with marked disturbance of nutrition. The child grows thinner, paler, and weaker ; his expression is distressed ; he sleeps badly at night, often asking for drink, and is disturbed by wandering abdominal pains. The temperature may rise slightly in the evening, but there is seldom marked pyrexia.
If there be no intestinal catarrh, the bowels may be confined, and the effect upon the child's general health is much less pronounced. He still looks ill, is troubled by flatulent pains, and is pale and weakly ; but nu trition may be fairly performed, and the child may even appear stout, although to the touch his limbs feel soft and flabby (see Ulceration of Bowels).
When caseation of the glands is associated with tubercular peritonitis —and it is to this combination that all old descriptions of tabes mesenterica apply—the symptoms are those of the peritoneal disease, and the case is a very serious one.
Scrofulous mesenteric glands are not always easy to detect. The belly is so often distended in children, with flatulent accumulations, that it may be difficult to force the parietes sufficiently inwards to reach the swollen bodies. Moreover, a certain tension of the abdominal wall, more or less voluntary, may still further increase the difficulty. The enlarged glands lie about the middle of the abdomen, in front of the spine. If the mass be a large one, pressing the abdominal wall directly inwards will usually de tect the swelling at once. In cases where the increase in size of the glands is inconsiderable, it is better to make pressure laterally, bringing the hands together from the sides towards the centre, so as to catch the little mass between the fingers.
If the glands are large enough to press upon the parts around, there may be oedema of the legs and scrotum from pressure upon the vena cava. This, however, is exceptional. A very small amount of pressure will' be sufficient to cause dilatation of the superficial veins of the abdominal wall ; and most cases of enlarged mesenteric glands are accompanied by this phenomenon. Cramps in the legs are said to be sometimes caused by pressure upon the nerves of the abdomen ; and ascites may be the conse quence of pressure upon the portal vein by the glands occupying the hepatic notch.