204 



ELIMINATION OF UREA. 



nutrition, &c., in the " Medical Times and Gazette," 

 March, 1865. The cell may thus take up a quantity 

 of material, convert it into new constituents, and dis- 

 charge these into its duct, without itself undergo- 

 ing any appreciable alteration either in form or 

 weight. 



A large quantity of urea or uric acid may, I think, 

 'be "eliminated" from the blood without the destruc- 

 tion of a vast number of renal cells. Lactic acid, and 

 lactates, and ammoniacal salts may be " eliminated " 

 by the agency of the cells of the sweat glands without 

 these cells being destroyed and replaced by new ones. 

 Other lifeless soluble substances may be separated 

 from the blood and eliminated in the same way, but 

 it is very improbable that the cells of secreting organs 

 should also attract towards them particles of living 

 matter and afterwards " eliminate " these in an unal- 

 tered and living state. 



I would remark here that when the eliminative act 

 does undoubtedly involve the destruction of the organ 

 of elimination, we have an arrangement very different 

 from that observed in the permanent or true glands 

 possessing ducts. The secreting organ in that case 

 is a closed follicle, like the " solitary glands " and the 

 glands constituting Peyer's patches in the alimentary 

 canal. The little " cells " or masses of germinal mat- 

 ter, of which the gland is composed, grow and mul- 

 tiply, and retain in their substance at least a great 

 part of the nutrient pabulum they take up. The mass 



