274: THE TISSUES. 



some extent retained. But it by no means follows, as Virchow 

 asserts, that all the nuclear fibres are hollow tubes for the nutrition 

 of the white fibrous tissue blended with the elastic. On the con- 

 trary, Kolliker maintains that all fine elastic fibres, which no longer 

 present any traces of the original cell, are solid, and are useful only 

 so far as they are elastic as those of the areolar tissue, of the co- 

 rium of the skin and serous and mucous membranes, of the fascia, 

 the perimysia, the periostea, the dura mater, and the walls of vessels. 

 For the cornea alone, where the elastic tissue remains in quite an 

 embryonic condition, does he adopt Virchow's hypothesis. In any 

 instance or any part where the elastic tissue is still undeveloped, 

 this may be the case also ; but, if so, this result is secondary and 

 incidental, and not the definite object of the tissue under consi- 

 deration, as Yirchow maintains. Donders maintains that all cell- 

 membranes consist of a substance identical with, or at all events 

 very similar to, elastic tissue. This opinion rests, on the one hand, 

 on the supposed development of elastic tissue, and especially of 

 nuclear fibres, from the walls of cells ; and, on the other, on the 

 circumstance that certain membranes and textural elements, which 

 in their physical and chemical properties closely approximate to 

 elastic tissue (e. g. nerve-sheaths), may be found to be formed from 

 cell-membranes. (Lehmann.) We cannot, however, accept this view 

 in its general application ; for the walls of very young cells, of 

 cytoid corpuscles and blood-cells, and the cells of the deepest layers 

 of compound epithelia, are readily soluble in acetic acid and in 

 very dilute alkalies. 



If the elastic tissue is removed or destroyed, it is not regenerated; 

 but an imperfect areolar tissue takes its place. Pathological new 

 formations of it are, however, not rare. 



The growth of the yellow fibrous tissue is secured by an increase 

 in size of each fibre, as well as by the formation of new ones, doubt- 

 less. Kolliker found that the fibres in the ligamentum nucha3 of 

 the calf are considerably finer than those of the ox; and that in 

 the new-born child not a single true elastic (coarse) fibre exists, but 

 only the nuclear (fine) fibres. 



Pathological New Formations of Elastic Tissue. 



Fibres of this tissue often occur in pathological epigeneses, in great 

 numbers and in considerable masses; the contiguous fibres being 

 also interwoven into a close and fine lattice-work, presenting the 

 same morphological conditions as coagulated (fibrillated) fibrine, and 



