OF THE SIMPLE FIBROUS TISSUES. 



225 



Fig. 19. 



should be applicable in one direction only, as is the case in Tendons and in most 

 Ligaments, we find the bands or fasciculi of fibres arranged side by side with 

 considerable regularity; and the larger tendons are shown by transverse section 

 to be made up of numerous aggregations of this kind, which are held together, 

 whilst to a certain degree kept apart from one another, by the interposition of 

 Areolar tissue. When, however, the traction is liable to be exercised in various 

 directions, the fasciculi of primitive fibres are observed to cross each other 

 obliquely; this decussation is observable in many ligaments, but still more in 

 those fibrous structures which serve as protective capsules to softer organs. 

 This tissue receives very few bloodvessels, and still fewer nerves; indeed, it 

 seems doubtful whether, in many fibrous structures (as tendons), nerves are 

 normally present at all, except on the sheaths of the bloodvessels. From the 

 time when it has attained its complete development, this tissue seems entirely 

 destitute of any vital endowment, and its physical actions are not of a kind to 

 induce disintegrating changes in its substance, with any considerable degree of 

 rapidity. Hence, although it is very rapidly regenerated by the formative 

 powers of the blood, after the destruction of a portion of it by disease or 

 accident ( 224), it does not seem to undergo much interstitial change during 

 the ordinary performance of its functions. 



221. The Yellow fibrous tissue (Fig. 19) exists in the form of cylindrical 

 fibres, easily separable from each other longitudinally, except when they branch 

 and inosculate ; they have a dark decided border ; and their usual diameter, 

 in the tissues of which they are the principal components, is about l-7500th of 

 an inch, though they are sometimes 

 nearly double, and sometimes scarcely 

 one quarter of that thickness. One of 

 their most marked peculiarities is 

 their tendency to break off abruptly, 

 the broken ends curling back upon 

 themselves ; and this suggests the idea 

 that they are composed of linear aggre- 

 gations of particles of a very definite 

 character. 1 The composition of this 

 tissue is very different from that of the 

 white ; for it is but little changed by 

 long boiling ; and although the decoc- 

 tion slightly gelatinizes on cooling, 

 yet the small amount of gelatin thus 

 indicated is probably derived from the 



white fibrous element of the areolar tissue, with which the elastic tissue is 

 usually penetrated. It is unaffected by the weaker acids, and undergoes no 

 solution in the gastric fluid; and it preserves its elasticity for an almost 

 unlimited period. According to Scherer, the yellow fibrous tissue from the 

 middle coat of the arteries consists of 480, 38H, 6N, 160 ; which (taking 

 Liebig's formula for Protein) may be regarded as 1 Protein +2 Water. When 

 burned, it leaves 1.7 per cent, of ash. It is always readily distinguished from 

 the white fibrous tissue, under the microscope, by its complete resistance to 

 acetic acid. There is less tendency to spontaneous decomposition in this tissue, 

 than in any other of the soft and moist portions of the fabric. It requires but 



1 In the ligamentum nuchae of the Giraffe, indeed, the fibres are marked with peculiar 

 transverse striations, strongly resembling those of the hairs of the Mouse and other 

 Rodents, and, as in them, probably indicative of a cellular organization. (See Mr. 

 Quekett's " Catalogue of the Histological Series contained in the Museum of the Royal 

 College of Surgeons of England," vol. i. pi. v. fig. 10.) 



15 



Yellow Fibrous Tissue, from Ligamentum Nuchse of 

 Calf. Magnified 65 diameters. 



