PRINCIPLES OF VETERINARY SURGERY 21 



stages of growth. The youngest forms are small, round 

 cells with a large, deeply staining nucleus and a small rim of 

 protoplasm. As the cell increases in size it takes on more 

 body, its nucleus becomes vesicular, and we have the so- 

 called epithelioidal cell. These throw out protoplasmic pro- 

 cesses and become typical fibroblasts, the immediate ante- 

 cedents of the connective tissue fibres. There are many other 

 cells present in granulation tissue, which may be summar- 

 ized as follows: 



1. Giant-cells. — These may be formed by repeated di- 

 vision of nuclei in the same cell, or by the union of several 

 cells. Giant-cells usually attend any new formation of tissue. 

 They are oval in shape, from 50 to 100 ^ in diameter, and 

 contain many nuclei scattered throughout their protoplasm. 



2. Plasma cells. — The protoplasm of these cells is usu- 

 ally distinctly granular, and sometimes consists wholly of 

 oosinophile granules or of fine granules taking a dark stain. 

 The nuclei are dark, circular, and often multiple. Origin not 

 definitely known. 



3. Leucocytes. — Lymphoid cells and polymorphonu- 

 clear leucocytes are usually present in large numbers. 



4. Mast-cells. — These cells are characterized by small 

 spheric granules which stain deep blue. 



Eventually the granulation-tissue cells are replaced by 

 connective tissue fibres which form more or less of a scar 

 or cicatrix. This is the result of the new tissue becoming 

 more and more dense, and undergoing shrinkage until finally 

 the blood vessels are crowded out, the cellular elements are 

 decreased in number and a firm mass of contracted fibrous 

 tissue makes up the cicatricial scar. 



Sometimes the granulation tissue forming is of such a 

 low type that it never becomes adult tissue. This is true 

 of the tubercles of tuberculosis and glanders, which are 



