90 THE TISSUES 



granules. In man pigmented connective-tissue cells occur in the 

 skin, chorioid and iris. 



The so-called wandering cells (Fig. 31) are not properly a part of 

 connective tissue, being merely amoeboid white blood cells (see page 





* - .»wr'.": _.-— J • ■-'-••M... ■:< : .' - / 



/..0% /■■'/ //i"\\s/./ ^-^^^^ \ 



lArn 



.^-"-f ■■y^%^:mw\ \ \ 



1. / , / .- , r~-*:'V<-v% — '(~< » 



/ V/ --T' , ' \ \ ::;*^:xi. 



,...- .- ,- -._ . -...,.. . _= ; ', 



Fig. 34. — Section of Human Cornea cut Tangential to Surface. X350. (Technic 

 8, p. 10 1.) Connective-tissue Cells with Anastomosing Processes, stained; Intercellular 

 Substance. (Ground Substance and Fibres), unstained. 



Ill) which have passed out from the vessels into the tissues. They are 

 not pecuhar to connective tissue, being found in other tissues, e.g., 

 in epithelium. 



The Intercellular Substance.— (a) Fibres. White or fihrillated 



fibres are bundles of ex- 

 tremely fine fibrillae (0.5/x 

 in diameter) (Fig. 32). The 

 fibrillae lie parallel to one 

 another giving the fibre a 

 striated appearance and are 

 '>^^% .€&^^i^'''^^ ^^^^^- •« , M%W^' united by a small amount 

 '^■"' s^S:^^!^ i^^^^ ^Sff of cement substance. The 



, ^ , . ^ „ fibrillae do not branch. The 



Fig. 35. — Pigmented Connective-tissue Cells 



from Chorioid Coat of Human Eve. X3S0. fibre bundles, on the other 

 (Technic 7, p. 100.) " ^^^^^ ^^^^^^^ dichotO- 



mously and anastomose. White fibres are soft. and flexible but very 

 slightly elastic. Chemically they consist of an albuminous material 

 known as collagen and, on boiling, yield gelatin. 



Yellow or elastic fibres are apparently homogeneous, highly re- 

 fractive fibres, varying in diameter from i to loju (Fig. 32). They 

 branch and anastomose, forming networks. The smaller fibres are 





