TISSUES, ORGANS, AND SYSTEMS. 88 



§ 25. 

 Osseous Tissue. — Morphologically, the osseous tissue consists 

 essentially of a ma- Fi g . 31. 



trix, and, scattered , .jn iitj-«o 

 through it, of a mul- la- 

 titude of microsco- ^~" /> 

 pic cavities, the bone filsP^i b 

 corpuscles, or hint nee, 



of 0-00G — 0-01 1 J 



in length, 0-003 ^»i 



— 0006"' breadth, l 



and 0-002— 0-00 i"' thickness. The former, of a white colour, is 



Fig. 31. A portion of a perpendicular section of a parietal bone, x 350 : a, lacunas 

 with pale only partially visible canaliculi, filled as in the natural condition with fluid ; 

 b, granulated matrix. The striated parts indicate the boundaries of the lamellae. 



Kolliker is simply ordinary connective tissue, in which the collagenous element is not 

 yet or but little formed. Its development may be readily traced in the most super- 

 ficial layer of the skin and mucous membranes, or in the tooth-pulp, or the so-called 

 actinenehyma of the enamel organ in the calf, &c. The epiglottis of the kitten is 

 particularly to be recommended, as this tissue can be observed passing on the one 

 side into the homogeneous layer of the corium nest to the epithelium, and on the 

 other into the so-called fibro-cartilage of the epiglottis. 



In all these cases, the mode of development of the areolated connective tissue is 

 essentially similar to that observed by Remak (Ueber die Entstehung des Binde- 

 gewebes, &c, Mull. ' Archiv,' 1852, I,) in the Frog. The layer of the tissue next the 

 epidermis or epithelium, is composed of a nearly homogeneous substance (matrix), 

 in which lie corpuscles (so-called nuclei), the whole in fact corresponding exactly 

 with embryonic cartilage. Internal to this, vacuolar cavities have been formed in the 

 matrix between the corpuscles, the substance of the matrix appearing as bands or 

 fibres between these vacuolar. The latter enlarging, the substance of the matrix is more 

 and more broken up into bands, in which dilatations remain where the "nuclei" 

 are situated, so that the bands often resemble fusiform or stellate cells. A structure 

 of this kind which undergoes no further chemical or morphological alteration, consti- 

 tutes the gelatiniform connective tissue; and it is unquestionable, that its subsequent 

 conversion into perfect areolated connective tissue is effected, as Professor Kolliker 

 states, by the direct passage of these fusiform bodies into the pseudo-fibrillated bundles 

 of the collagenous substance. But it is their outer portion only, thai therefore which 

 corresponds with the matrix of cartilage, which becomes thus changed — the elastic 

 element being developed as before, not from separate cells, but by the chemical 

 metamorphosis of the matrix immediately around the cavity which contains the 

 " nucleus," and in various other directions. 



That the pseudo-fibrillated portion of the connective tissue corresponds with the 

 matrix of the cartilages is then, we think, certain. Whether with Remak we are to 

 regard both these as cell-walls, or with Reichert as intercellular substances, must be 

 discussed hereafter. (See General Appendix.) — Eds.] 



