304 LYMPH. 



capillaries than is necessary for the nutrition of the organs and 

 the formation of the secretions (so that a large proportion of 

 unchanged plasma is blended with the substances which are 

 either metamorphosed by nutrition, or have not passed into the 

 secretions), but it is further proved by innumerable physiological 

 facts, that the fluid which is resorbed by the lymphatics undergoes 

 further metamorphoses in its passage through the lymphatic 

 glands. It may be inferred from the appearance of cells which, 

 however, are probably not formed until after the passage of the 

 absorbed fluid through the glands (at least in the animals provided 

 with lymphatic glands), that the lymph contains not only the 

 products of regressive metamorphoses, but even true plastic sub- 

 stances. The lymph of certain organs appears to possess so high 

 a degree of plastic force, that blood-corpuscles are even formed in 

 it; the lymph of the spleen frequently, and indeed generally, 

 contains blood-corpuscles, as has been already noticed. According 

 to Huschke,* the Malpighian corpuscles of the spleen are nothing 

 more than dilatations of the lymphatics, but from the coincident 

 observations of Gerlachf and Schaifner,J it seems much more 

 probable that this organ is one of the main factories for the 

 blood-corpuscles. If, however, the lymph must vary according to 

 the quantity of unchanged blood-plasma which it may contain, we 

 find a new ground established for the great differences which it 

 presents in different parts, when we consider that the chemical 

 constitution of the transuded plasma depends upon the character 

 of the capillaries of each organ, that is to say, upon their width, 

 upon the density of their walls, the velocity with which the blood 

 streams through them, &c. Gerlach draws especial attention to 

 the fact that the spleen has very wide blood-vessels, which may be 

 classed amongst the capillaries from the absence of a circular 

 fibrous coat, and which would appear from the thinness of their 

 walls to be better adapted than the capillaries of other organs to 

 admit of the transudation of a perfectly unchanged blood-plasma, 

 that is to say, of an intercellular fluid, and would therefore afford 

 the most abundant materials for the formation of cells. If we 

 may regard certain normal or even dropsical exudations in the 

 animal body, as for instance, the transudations of the choroid 

 plexus of the brain (which are very remote from the lymphatics 

 that lie only on the periphery), as the direct secretions or 



* Lehre von den Eingeweiden. S. 175,ff. 

 t Zeitechr.f. rat. Med. Bd. 7, S. 7582. 

 t Ibid. p. 345 354. 



