100 FORMATION OF CUTICLE DURIN(3 HEALING. 



or combined with it at tlie time of its origin from 

 the bioplasm. The gTadual production of these 

 fibres may be studied under the microscope during 

 the coagulation of a drop of liquor sanguinis. 



146. Formation of cuticle cluriug the healing of a 

 wound, &;c. — A modified form of cuticular tissue 

 may be produced in a manner different from that 

 described in § 116. Where the healing process pro- 

 ceeds over an extensive surface after the removal 

 of a considerable portion of skin, new cuticle is 

 at last formed. The formation of new cuticular 

 textui-e does not only spread gradually towards 

 the centre of the space from the intact cuticle at the 

 margin of the wound, but new points of cuticle for- 

 mation are seen to originate as little islands even 

 in the central part. This cuticular tissue must be 

 formed by masses of bioplasm, which have descended 

 from white blood corpuscles, many of which are 

 usually found upon the surface of a healing wound, 

 having escaped when very small with the serum of the 

 blood through the thin walls of the capillaries.* It must 

 be remembered that the particles of bioplasm concerned 

 are the descendants of white blood corpuscles which 

 have themselves descended from embryonic masses of 

 bioplasm formed at a very early period of develop- 

 ment before many of the tissues were formed, and at a 

 time therefore when the capacity for the production 

 of diverse structures was greater than at a later pei'iod. 

 The white blood corpuscles are the only masses of 

 bioplasm of the adult that could inherit the diverse 

 powers of embryonic bioplasm, and this perhaps may 

 be the explanation of the greater degree and variety 

 of formative capacity possessed by these as compared 

 with other living particles. 



14'3. Formation of tilirous tissue in bealiu§^ of 

 wounds. — When a wound in the substance of a tissue 



* "On the Germinal Matter of the Blood." Mic. Journal, 

 1868. 



