ORIGIN OF THE ABSORBENTS. 341 



lymphatics are known to originate, it is most probable, though 

 not yet fully demonstrated, that it is from the cellular woof 

 alone they take their rise. In fact, the organs in which this 

 tissue does not enter, are the only one from which no lym- 

 phatics originate, viz. the nails, horns, epidermis, ivory of the 

 teeth, etc. Mascagni* and Cruveilhier have observed, in 

 respect to the cellular tissue and the serous membranes, so 

 many lymphatics in their combination as to be induced to 

 believe that they are formed of these vessels. The microscopi 

 cal researches of Fohman, Arnold, and Treviranus upon this 

 subject, have led them nearly to the same conclusion ; the two 

 first believing that the cellular tissue acts the part of a sponge 

 to the absorbents which have their radicles in it, and that its 

 filaments are probably composed of very minute elementary 

 lymphatic vessels. Treviranu3,f in some observations upon the 

 lower animals, (especially in the tortoise,) by the use of a glass 

 of very great magnifying powers, was led to believe that the 

 absorbents do take their origin in the cellular tissue which 

 appeared to be composed of elementary cylinders, closely inter- 

 laced together, some twisted, some zigzag in shape, and of such 

 minuteness as to have a diameter only the 0.0016, to 0.0002 of 

 a millimetre.^ Some of these appeared to unite together, and 

 formed larger cylinders, which went out from the mass, united 

 with others of the same kind, and thus formed trunks of 0.001 

 to 0.0023 of a millimetre in diameter, which had the appearance 

 of lymphatics, and opened into the lymphatic vessels. Thus 

 he believes, that when ultimately analyzed, the lymphatic ves- 

 sels will be found to originate on all the free surfaces of the 

 body, in the midst of the tissues, as well as in the intestinal villi, 

 by elementary tubes belonging to the cellular tissue, which con- 

 stitutes the basis or web-work of the organs ; and which tubes 

 have appeared to him on the villi and free surfaces of the body, 

 to terminate in vesicles that seemed in some parts to be pierced 

 with a hole. 



* Vasor. Lymph. Corp. Human. Hist, et Tconogr. Sienne, 1787. — 

 I Bertrage Zur Aufklaerung der Erscheinungen und Gesetze, der organits- 

 chen Lebens. 1836, page 100. — 



I A millimetre equals the 0.039379 part of an English inch. — 



29* 



