HISTOGENESIS OF CONNECTIVE TISSUE. -, ; 



In a Fund id us embryo of 6 mm. total k-n^th se\ -oral day- after 

 hatching- I find in the median fin between the double layer 

 of cutaneou- epithelium tin- tir-t -;-n- . .f tin- dermal fin-ray-. 

 R!ood-ve el- have not entered, and between the tin-ra\- are 

 fr\v if any connective ti ue fibers, certainly HOIK- in the distal 

 portion of tlu- fin. nvadiirj the ba-e of the fin is a ma-- of m -- 

 in hymal cell-, mostly of the numd cell type. s < al iT'-d through 

 the fin are, here and there. i-lated c< mnect i\ e ti. ue cell- in 

 very limited number-, di-tribtited over an area repre-i nt iii^ 

 the proximal one half or two third- of the tin. and forming a -on 

 of -kinni-h line, as it urn-, in advance of the army of round cell-. 

 I Stellate cells e.m often be di-linctly seen in the li\ in- 



animal, l.aier. coniiecii\e ti--ne cell- in abundance \\ander into 

 the tm and fiber- appear. Rut it cannot be -aid that the tilur- 

 appear in ad\ame of ihc cell-, for the "-kirmi-h line" pivc.de- 



the appearance ot tiber-. t ! dvance eiu becoming later 



intermingled \\ith tho-e of the -ub-e(|iH'nt in\a-ion. 



The ad\allie cell-, like all other -tell. lie connective ti lie 



cell- in the tin- o| einbr\o ti-ln -, I tind to be actively anxeboid, 



capa!'!' "iil\ o| motion bn: me < \ient of loioinotion. 



>iii(f ihe-e till-, are !ia\ellinu :hrou-h an area in which liber- 



oiil\ ju-t beginning to appear, the location of early fibers al 



point - idati\el\ di-tant from the c-ll in "fixed" li ue al once 



lo-e- ii ificance and thus robs the theorj of the extracellular 



origin of fibei -iiplon- M \ ob-er\ at imi- 



ma\ be readilx \etitied on an\ li\iirc, free-swimming l-'innhilns 



embryo within the fir-i week after hatching 



1 inni tive li--ue liber- ma\ be -ti|)po-ed to ari-e a- a |)rodin i 

 of se< retioti of the me-ench\ ma! i ell-, the extracellular deposition 

 of fiber- tliu- occnrrini; under the intliience of the cell-. Thi- 

 i- bin a -liijit deviation from the -trict ext r.n ellular origin |>re- 

 supposed by the theon ot Ibnle and Kolliker. Such -i-cntimi 

 mn-t appear either in fluid form or a- granule-. In either case 

 it i- difficult to conceive why the -ecretion -hoiild take on a 

 linear form it the cell- remain Stationary, and -till more difficult 

 if the cell- are in motion, mile-- that motion be extrcmelv -lo\\ 

 and in one direction only. 



Rv ob-er\ aiion of the tins of c-mbr\'o fi-h. chieth' h"undulus, 

 I ha\e been able to ol that the -pindle cell- ot embrvom'c 



