TISSUES, ORGANS, AND SYSTEMS. 71 



the transversely striated muscles, but differ from them in 

 the absence of any special investment comparable to the sarco- 

 lemma, and in their smaller mean diameter (0004;"' — O005'"). 

 They are either long, slightly wavy cords, of uniform thick- 

 ness throughout, which arc not directly connected together, 

 but arranged in different ways near and above one another, 

 forming great lamellae and bundles ; or they coalesce like the 

 elastic networks into meshes, and thus form what I have called 

 the reticulated connective tissue. In rare cases the bundles 

 appear not to be composed of fibrils, but are more homogene- 

 ous, as in the neurilemma, where they are known as Remak's 

 fibres. Besides this form of connective tissue, there exists a 

 second, rarer kind, in which neither bundles nor fibrils can 

 be clearly distinguished, but only a membranous or more or 

 less solid, finely granulated, or slightly striated, even per- 

 fectly homogeneous, clear tissue ; homogeneous (or Reichert's) 

 connective tissue. The other elements which occur in con- 

 nective tissue present nothing remarkable, and will be more 

 particularly treated of in their proper places in the special 

 part. 



The chemical relations of connective tissue are well known : 

 proper connective substance when boiled yields common gela- 

 tine, and contains besides a fluid, whose nature, on account of 

 its generally minute quantity, cannot be investigated. Only 

 where it exists in considerable proportion, as in the gela- 

 tinous connective tissue of embryos, can the presence of much 

 albumen and mucus be easily demonstrated in it. The che- 

 mical qualities of the other constituents of the connective 

 tissue will be spoken of in their place. 



Connective tissue is of utility to the organism according to 

 its composition, — sometimes as a solid unyielding substance ; 

 sometimes as a soft support for vessels, nerves, and glands ; 

 sometimes, finally, as a yielding tissue, filling up spaces and 

 facilitating changes of position. Where elastic elements are 

 present in it in great quantities, its nature alters ; and a great 

 abundance of fat or cartilage cells gives it an unusual softness 

 or resistance. The connective tissue is invariably developed 

 from cells, and, in fact, from fusiform or stellate vesicles, 

 which become united into long fibres or networks, and 

 often break up into fibrils before their union. The mode 



