482 WOUNDS. 



scab. To avoid these unfavourable concomitants, perfect rest 

 must be enjoined, non-interference, and a cooling diet. Collodion 

 makes a good artificial scab. 



Such, tlien, are the several methods of healing observed after 

 wounds of the soft parts, and in connection with them we have 

 the perfecting of scars. In the perfection of scars two things 

 may be observed, namely, their contraction, and the gradual 

 perfecting of their tissues. A process of contraction is always 

 associated with the development of granulations, and this is illus- 

 trated by the smallness of the scar in comparison with the original 

 wound. This contraction of both the granulation and the scars 

 is regarded as some vital power of contraction, and of a necessary 

 mechanical effect of the changes of form and construction that 

 the parts undergo. The same change ensues in the organization 

 of inflammatory products, as in false membranes, indurations, 

 and thickening of parts. In all these cases the form of the cell, 

 while elongating, as before described, into a fusiform body, is so 

 changed that it will occupy less space. The whole mass of the 

 developing cells becomes more closely packed, and the tissue 

 they form becomes much drier ; with this, also, there is a diminu- 

 tion of vascularity. Thus, there results a considerable decrease 

 of bulk in the new tissue as it develops itself; and this decrease, 

 beginning with the development of the granulation ceUs, con- 

 tinues in the scar. The improvement and perfecting of the 

 tissue of the scar is again a very slow process. The principal 

 changes by which it is accomplished include the removal of 

 rudimental textures, the formation of elastic tissue, the improve- 

 ment of the fibrous or fibro-cellular tissue, and of the new cuticle, 

 till they are almost like those of the natural formation — except- 

 ing always that the true skin is not reproduced with its hair 

 follicles, &c. — and the gradual loosening of the scar, so that it 

 may move easily on the adjacent parts. The tissue of the scar 

 extends dow^n deej) into the wound, fastening itself immoveably 

 upon its surface ; but after a time it becomes more elastic and 

 looser, and the morbid adhesions are freed. Thus we see injuries 

 to the joints followed by much stiffness ; this stiffness — dej^nd- 

 ing upon the adhesion of the scar to the deeper-seated parts — 

 gradually disappears, and the scar itself becomes more and more 

 pliant, but it never assumes the exact characters of the original 

 tissue, and a scar remains a scar throughout the animal's life. 



