274 ABSORPTION. {CHAP. xxVi. 



seem to do by their vital contractility. As the contents advance 

 the vessels diminish in diameter. It is usual to find the lymphatics 

 empty and collapsed some time after death. 



The lymphatic glands are, for the most part, flattish oval bodies, 

 of firm consistence and light colour, situated in the course of the 

 lymphatic and lacteal vessels, these vessels being styled afferent as 

 they enter the gland, and efferent as they leave it. The glands 

 vary from the size of a millet-seed to that of an almond. They 

 usually lie loosely in the areolar texture, well protected from 

 injury by their mobility, and if near the surface of the body^ 

 by the disposition of the neighbouring bones or muscles. They 

 have a firm but delicate proper capsule, which is continuous with 

 the outer coat of the vessels, and which sends processes inwards 

 upon the blood-vessels and lymphatics which penetrate the 

 glands. 



The general structure of these glands has long been known, being 

 well displayed by mercurial injections (fig. 170, A). This metal, 

 when thrown into an afferent vessel, shows that this divides into 

 minute branches, most of which spread out over the gland before 

 entering it, and that the efferent vessels have a similar arrangement 

 on the opposite side. The mercury readily fills the entire gland, 

 and escapes by the efferent vessels. The surface of the gland, when 

 occupied by mercury, exhibits either a very close plexus of tortuous 

 minute vessels, or else a congeries of apparent cells ; and while there 

 has been no doubt of the continuity of the internal tracts of the 

 gland with both the afferent and efferent vessels, the question has 

 been discussed, whether these tracts are simply convolutions of 

 tubes, or cellular lateral offsets from channels traversing the gland 

 in a more direct course. Both of these views may possibly be true 

 in different cases, or probably the convoluted vessels of the gland 

 may be themselves dilated at intervals into cells which, from 

 their mode of package, may simulate detached cavities, as in 

 the well known arrangement of the vesiculae seminales. In con- 

 firmation of this last view it may be observed, that the tracts of 

 the gland are usually more capacious than the ramifications of 

 the afferent and efferent vessels which immediately communicate 

 with them. 



A more important question concerns the changes in the tissues 

 forming the walls of the afferent vessels on their entrance into the 

 gland, and this has been ably illustrated by Professor Goodsir. He 

 describes the outer areolar coat as passing to form the capsule of 

 the gland, and the proper coat to become extremely thin, especially 



