234 



SPECIAL HISTOLOGY. 



nective tissue. These fibrils may also be distinguished on a transverse 



section, as minute dark points, or as lines 

 radiating from the coarser points exhibited 

 in the section (Fig. 96) ; and they are still 

 more evident in longitudinal sections, in 

 which, more especially, the whole of the 

 fibrous system just described comes very 

 readily into view. In such sections, also, 

 it is evident that, in every case in which 

 the formative cells of which the fibres are 

 constituted still retain a certain degi'ee of 

 independence, very distinct elongated nu- 

 clei exist in them. Besides these elastic 

 fibres, the tendons, in certain situations, 

 contain cartilage-cells [vid. infra), as well as common fat-cells, particu- 

 larly in the more lax tendons, as in the tendinous fibres of the in- 

 tercostal muscles, of the triangularis sterni, masseter, &c. 



The transversely banded aspect of the tendons, to which their glisten- 

 ing appearance is due, depends simply upon the numerous curves of 

 their fibrils, which correspond with each other throughout the fasciculus ; 

 this appearance is destroyed when the tendon is forcibly stretched, and 

 merely indicates its innate elasticity, which comes into play in the 

 relaxed condition. 



The primary tendinous fasciculi, according to Donders and Mole- 

 schott, are seen in transverse sections treated with potass. This reagent, 

 according to them, separates the secondary fasciculi into smaller ones, 

 each of which consists of from 5 to 10 primitive fasciculi. In moistened 

 transverse sections of dried tendon of man and the mammalia, I can 

 very distinctly recognize the primitive fasciculi, although they have 

 extremely delicate outlines. The appearance thus obtained affords an 

 indistinct image of that presented in a transverse section of muscle. 

 Even the very fibrils are, in this way, rendered distinct, a circumstance 

 which appears to me of the greatest importance. When a transverse, 

 not a longitudinal, section of tendon moistened with water or acetic acid 

 is examined, there will be observed in all the secondary fasciculi, or in 

 the primary when they can be distinguished, if not in all, yet in most 

 cases, an extremely regular and minute punctation, nearly like that of 

 the muscular fasciculi (Fig. 90), only not quite so distinct. The appa- 

 rent granules are pale, round, of the same diameter as the tendinous 

 fibrils which are obtained in other ways, and can be explained in no 

 other manner than as beinn; the transverse sections of such fibrils. 



Fig. 96. — Tendon of the tibialis posticus (Man), magnified 60 diameters: a, secondary fas- 

 ciculi; b, thicker nuclear libres ; f, interstitial connective tissue. 



