DEVELOPMENT OF CONNECTIVE TISSUE 71 



subsequently become fibrillated. The cell-processes, however, do not, 

 it is believed, ever form single fibrils, but always smaller or larger 

 bundles ; in this there is a marked difference between the development 

 of the white connective tissue and that of the elastic fibres, as will 

 immediately be seen. The bundles of white fibres probably become en- 

 larged by a further fibrillation of the part of the cells in contact 

 with tliem, the cells at the same time themselves increasing in size and 

 probably also in number. 



The above description of the development of the white connective tissue, 

 which is principally founded upon the results of actual observation on the 

 mammalian embrj-o and young animal, is substantially the same as that 

 given by most recent observers who have investigated the subject.* and in 

 many respects accords with the original description of Schwann. It is right, 

 however, to state that a very different view is held by several distinguished 

 authorities, according to whom the cells themselves have no du-ect share in the 

 formation of the fibrils, which are believed to be developed as an indc'i^endent 

 deposit in the muco- albuminous matter which lies between the cells. 



"With regard to the formation of the elastic fibres, little is positively 

 known, but it would appear that they also are formed from cells, 

 probably of a dififerent nature from those which generate the white con- 

 nective tissue. The fibres appear to be formed of the processes of the 

 cells which grow out and branch, becoming connected with processes 

 from other cells. The conversion into elastic substance seems to occur 

 first at the extremities of the processes and to proceed towards the 

 body of the cell : it would appear probable that it is the surface layer 

 of a fibre that is first clianged, for elastic fibres (presumably not fully 

 developed) are here and there met Avith which appear to present a 

 tubular structure ; for a prcci))itate may under some circumstances be 

 produced in their interior. "What becomes of the body of the cell is not 

 very clear : however, it would seem that in some instances, at least, 

 the connection of the elastic fibres with cell processes is retained even 

 in the fully-developed tissue (Thin) : in the pure elastic ligaments, on 

 the other hand, the cells are stated to disappear. 



The first appearance of the elastic fibres is described by Eanvier and others as 

 occiu'ring in the form of rows of granules or globules which subsequently ran 

 together. Such a mode of formation would explain the appearance of an in- 

 distinct transverse striation which has sometimes been described in those fibres. 



As in the case of the white connective tissue, it has been held by many 

 authorities that the elastic fibres are also fomied by a deposit (although of a 

 different nature) in the muco-albuminous fluid between the cells. 



In the formation of the special varieties of connective tissue, no 

 fibres are developed, but either the cells disappear altogether, their 

 place being occupied by muco-albuminous matter, as in the jelly-like 

 connective tissue ; or this matter is developed in but very small amount, 

 in which case the cells may either become flattened out, remaining co- 

 herent at their edges, as in the homogeneous membranes, or, some of 

 them becoming branched, and, intercommunicating by their processes, 

 may form a reticulum within the me?hes of which other cells are more 

 or less closely packed, as in the rctiform or adenoid tissue. 



* Max Schultze : Briicke (Obersteiner, and Kusnetzoff, Wiener Sitzb. Ivi. ); Strieker 

 (Breslauer, Arcli. f. mikr. Anat. v.) : Boll, Arch. f. miki-. Anat. vii. 



