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Status Lymphaticus and Sudden Death in Infancy Diseases of the Thymus

gm, gr, found, front, gland, considerable and lobes

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DISEASES OF THE THYMUS, STATUS LYMPHATICUS AND SUDDEN DEATH IN INFANCY It is made up ehietly of reticular tis.sue. It begins to take its part in the making of the blood (luring the last fLetal months; and grows according to Walcleyer, until the ehilil is one or even two years of age. After this it remains stationary until after pub erty, when it gradually diminishes in size, undergoing fatty degeneration.

As found post mortern, the size and weight of this gland-like organ varies considerably. Friedleben has established the following average figures, and they have been frequently confirmed.

Weight of gland at. birth 14.3 Gm. 214.5 gr.

From one to nine mouths 20.7 Gm. 310.5 gr.

From nine to twenty-four months ...... ....... 27.3 Gm. 409.5 gr.

From two to fourteen years............ ..... 27.0 Grn. 405.0 gr.

Front fifteen to twenty-five years 32 1 Gm 331 5 gr From twenty-five to lhirty-five years... ...... 3.1 Gm. 46.5 gr.

Wahleyer has found the remains of the thymus even later in life.

Anatomy.—The thymus consists of two lobes, faintly red in color. They are more or less pointed towards the upper part and rounded off toward the lower. They are bound together by loose conneetive tissue. The greater portion of the gland lies behind the manubrium and body of the sternum; but the sides and lower portion are covered by the folds of the mediastinurn and are forced away from the chest wall by the anterior borders of the lungs. This location explains the peculiar normal percus sion note of the thymus which is alluded to later on. It covers the peri cardium and the beginning of the great vessels posteriorly and also reaches down to the pulmonary veins. The upper pointed olges of both lobes cover the trachea. On the sides, the thymus is bounded by the innominate and common carotid arteries, the vagi and the phrenie nerves. Baek of the lobes, and in front of the vertebral column, are found the sym pathetic nerves. The neighborhood of so many important vital organs (see Fig. 951 renders them liable to serious injury in ease of disease with enlargement of the thymus.

Researches as to the functions of this organ arc not yet concluded. While formerly the thymus was thought of only in connection with the formation of the blood, there are now several authorities who aseribe to the gland a secretion like other glands. It is also supposed

to regulate the nutrition and growth of the hones and the brain, and also to aet upon the circulatory system, raising and lowering the Hood pressure.

In experiments upon. animals, it has been observed that intra venous injections of the thymus extract are often fatal, the animal dying in convulsions (Abelous and Billard, Svehla, Basch).

Observers are far from agreeing as to the consequences of extir pation of the thymus in young animals, for instance, Basch claims to have noticed a considerable increase in the elimination of lime, and considerable interference. with the growth of the bones, after its re moval; on the other band, Sinnhuber and lately Fisch] insist that there are no characteristic consequences following the operation.

Pathology.—Since Friedieben, by his thorough iTsearches, re duced to a minimum the importance of the thymus in the diseases of infancy, many other voices have been raised in doubt during the last twenty years; so that at the present tinie we are in the thick of con tradictory opinions.

I. Hyperplasio of the Thymus.—The greater portion of these dis cussions is taken up with arguments as to whether hyperplasia of the thymus does or does not exist. The question is not an easy one to answer—When the clinician and the anatomist cannot agree who shall guide the pathologist? The weights mentioned above are average figures, and are of no great value because the actual weights vary to so great an extent. For instance, at the end of the first month of life it varies front 2 to 31 Gm. (30-465 grains). In consequence, the statements of authors in regard to hypoplasia of the thymus, end generally as physiological studies. Occasionally one finds here and there extraordinary figures; as for instance, koppe's CLASC weighing 52.9 Gm. (793.5 grains). Again, Richter calls attention to the fact that thymus glands of considerable weight arc quite frequently found. If one takes the dimensions of the organ as a guide, he should remember that differences in the histological conduct of the same sized glands, may produce the most different weights.

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