228 



OF THE PRIMARY TISSUES OF THE HUMAN BODY. 



Fig. 22. 



Development of fibres from 

 cells : a, circular or oval nucle- 

 ated cells ; b, the same becom- 

 ing pointed ; c, the same become 

 fusiform, the nuclei being still 

 apparent ;d, the same elongated 

 into fibres, the nuclei having 

 disappeared. 



inflammatory adhesions and indurations. The cells first formed in the plastic 

 exudation are round, very slightly granular, from 1-1500 to l-2000th of an inch 

 in diameter ; they have a distinct cell-wall, which is readily brought into view 

 by the action of water, if not apparent at first ; and 

 they present a round dark-edged nucleus, whose sharp 

 definition distinguishes it from that of the colorless cor- 

 puscles of the blood, to which these cells otherwise bear 

 a close resemblance. It is in this nucleus that the first 

 developmental change shows itself, for it assumes an 

 oval form, and its substance becomes clearer and brighter. 

 Very soon, however, the cell itself elongates at one or 

 both ends, so as to assume the caudate, fusiform, or lanceo- 

 late shape (Fig. 22) ; and its contents become more mi- 

 nutely and distinctly granular, whilst the cell-wall thins 

 away or becomes blended with its enclosure. As the 

 cells elongate more and more, so as to assume the fila- 

 mentous form, they also arrange themselves in such a 

 manner that the thickest portion of one is engaged be- 

 tween the thinner ends of the two or more adjacent to 

 it; and thus fasciculi are gradually formed, of which 

 every fibre is developed from one elongated cell, except 

 where two or more cells have united end to end, so as 

 to form one long continuous filament. 1 In the produc- 

 tion of areolar tissue in inflammatory exudations or in 

 granulating wounds, the nuclei of these fibre-cells ap- 

 pear to waste and be absorbed ; but in the normal course 

 of development, which may be seen to take place on 

 this plan in the subcutaneous areolar tissue of the foetus, as well as in many 

 other situations, it is probable that they develop themselves into the " nuclear 

 fibres" of Henle", which constitute, in fact, the Yellow or elastic filaments that 

 are intermingled with the white in this tissue. 



224. The development of the White fibrous tissue by the fibrillation of a 

 nucleated blastema, without any intervening cell-formation, may be observed 

 in the organization of the material by which the filling up of subcutaneous 

 wounds is usually accomplished ; and seems to be the mode in which the first 

 production of tendons and ligaments is normally accomplished. The blastema, 

 when first effused, seems like a mere fibrinous exudation, usually containing 

 a quantity of finely-molecular or dimly-shaded substance, but having no appear- 

 ance of distinct nuclei ; these, however, gradually present themselves in it, as 

 if they were formed by the aggregation of molecules; and they presently appear 

 as oval bodies with dark hard outlines, which soon become elongated, and are 

 so firmly imbedded in the surrounding substance that they can scarcely be dis- 

 lodged. The blastema gradually acquires a more and more distinct fibrous 

 appearance, and at last exhibits a regular filamentous structure ; the nuclei 

 themselves undergoing little change during this time, but appearing to govern 

 the direction of the fibrillation. As the texture goes on to completion, the 

 nuclei are either absorbed, which seems to be the case in the connecting tissue 

 formed for the reparation of injuries, as well as in the normal development of 

 tendons; or they undergo a further development into <( nuclear fibres." 2 This is 

 effected by their extension at both ends, so that the nuclei thus prolonged meet 

 and unite ; their particles taking on that very uniform linear arrangement, by 



1 It was asserted by Schwann that each of these elongated cells splits up into several 

 filaments ; but Mr. Paget agrees with many other observers in considering this representa- 

 tion erroneous. 



2 See Henl^'s " Allgemeine Anatomic," traduit par Jourdain, torn. i. pp. 202, 406. 



