LYMPHATIC SYSTEM. 170 



related by this very ingenious author; but enough, I think, 

 has been said to show how cautious we -should be in making 

 conclusions with respect to the passages of the living body, 

 from experiments made on the dead, where, from the weakness 

 of the vessels and other circumstances, we are so liable to be 

 deceived. 1 



Thus, on taking a review of the doctrine, that the common 

 veins are the instruments of absorption, that doctrine appears 

 to have no other support than respect for the authority of our 

 predecessors ; for all the arguments in its favour are liable to 

 considerable objections (LXXXII). Let us next, therefore, in- 



1 Dr. Hunter and Dr. Monro found in theij experiments that injections readily 

 burst from the arteries into the lymphatic vessels, by the intervention of the cellular 

 membrane ; these experiments they at first considered (as Dr. Meckel does his) as 

 proofs of their having filled the natural passages; but more careful observations seem 

 to have now convinced the former of these gentlemen that such conclusions are fal- 

 lacious, and he now thinks that the injection may have burst into the sides of the 

 lymphatic vessel. See his Medical Commentaries, p. 5. 



(LXXXII.) It is now generally admitted that imbibition takes place 

 through the coats of veins, lymphatics, and other tissues, and that the 

 veins convey various matters into the system. Indeed, absorption 

 or wasting of a tissue may take place where, in the healthy state, 

 neither blood-vessels nor lymphatics can be found, as mentioned in 

 Note LXV * ; the same tissue may also become thickened ; among other 

 examples, those of hypertrophy and atrophy of the articular cartilages 

 may be mentioned : see 'Description of the diseased Joints in the Fort 

 Pitt Museum,' sect, ii, iii, 'Edinb. Med. and Surg. Journ.' vol. xlviii, 

 pp. 67-70. Mr. Toynbee a concludes that certain tissues are capable of 

 being nourished without the presence within them of blood-vessels. 

 And Mr. John Goodsir b has pointed out some organic processes in 

 which absorption and ulceration appear to be functions independent of 

 the vessels, which he considers as mere 'passive ducts in carrying 

 away the absorbed products. He concludes that, " the primitive cell 

 is primarily an organ of specific absorption, and secondarily of nutri- 

 tion, growth, and secretion." The old mechanical notion, entertained 

 in Hewson's time, of regular pores or orifices in the vessels for absorp- 

 tion and secretion is now exploded. With a good microscope, it is 

 most easy to see fresh cells, as those of pus or of the semen, swell from 

 imbibing water added to them. From the observations of Tiedemann 

 and Fohmann, it was supposed that the chyle could be absorbed from 

 the mesenteric glands of the seal by the veins only ; but Dr. Knox c 



a Phil. Trans. 1841, p. 188. c Edinb. Med. and Surg. Journal, xxii, 



b Anat. and Pathol. Obs. pp. 8, 14, 19, 23. 



34, 8vo, Edin. 1845. 



