TISSUES, ORGANS, AND SYSTEMS. 99 



"Die Structur der serosen Iliiute." Besides ■which, consult the works 

 of Virchow, Donders, Rcmak, and myself, cited above. 



§ 25. Osseous Tissue. — Morphologically, the osseous tissue consists 

 essentially of a matrix, and, Fig. 31. 



scattered through it, of a 

 multitude of microscopic 

 cavities, the bone corpuscles^ ^^^ ' ' ' " ' ' '-■ '■ -^ • ■■Mp;^ 'f^p-^ 



or lacuiiK, of 0-006-0-014 -— ^' ^^^^-^^^^ 



of a line in leno-th, 0-003- ., -^- -v ' 



O'OOO of a line in breadth, 5^ 

 and0-002-0-004of aline in . ii^^> ; 



thickness. The former, of i 



a white color, is sometimes more homogeneous, sometimes finely granular, 



Fio. 31. — A portion of a peipendictilar section of a parietal bone ; magnified 350 diameters : 

 a, lacunae 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. 



texture returns. The author justly remarks, that if the connective tissue consisted of separate 

 fibrils the impossibility of isolating them in the distended condition would be quite inex- 

 plicable. It is however intelligible, that in consequence of such an alteration in the con- 

 nective tissue its cleavability may be diminished or destroyed, which does away with the 

 necessity of supposing a fibrous structure. On the other hand, if a piece of tendon be 

 hardened by a strong solution of caustic potash, or by nitric or hydrochloric acids, no fibres 

 can be demonstrated in it (Bericht., pp. 40, 41). It is easy enough to verify the truth of these 

 statements, by treating a piece of tenduious tissue with acetic acid, when, as is well known, 

 the fibrillated appearance disappears; then keeping in view one of the distended and trans- 

 parent "bundles," slowly add a solution of caustic ammonia, the transparent mass will be 

 seen gradually to shrink, and eventually to resume what appears to be a most distinctly 

 fibrous appearance. 



The gelatinous or rather gelatinifnrm areulated connective tissue of Professor Kdlliker is simply 

 ordinary connective tissue, in which the collagenous element is not yet or but little formed. 

 Its development may be readily traced to the most superficial layer of the skin and mucous 

 membranes, or in the tooth-pulp, or the so called actinenchyma 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 next 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 essen- 

 tially similar to that observed by Remak (Ueber die Entstehung des Bindegewebes, &c., 

 JIull. •' Archiv," 1852, I.) in the frog. The layer of the tissue next the epidermis or epi- 

 thelium, is composed of a nearly homogeneous substance (matrix.) in which lie corpuscles 

 (so-called nuclei), the whole in fact corresponding exactly with embryonic cartilage. In- 

 ternal 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 vacuolce. 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 imdergoes no further chemical or morpho- 

 logical alteration, constitutes the gela'.iniforni conneclive tissue; and it is unquestionable, that 

 its subsequent conversion into perfect areolated connective tissue is efiected, as Professor 

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



