Osteoma. 



355 



nective tissue acts as a derivative of the periosteum. In fresh 

 specimens the periosteum and muscular connective tissue of 

 these cases appear to be merged into one mass of bacony, cartila- 

 ginous and rigid character; after maceration, brittle, papyraceous 



Fig. 05. 

 Osteoma on the horn process of a cow. 



and gland-like plaques and nodosities of bone are found along 

 the muscular attachments. 



Osseous growths of irregular and flat shape {ossiUcatio 

 raconosa, plana) and intermediate types approaching compact 

 osteomata have been encountered as isolated deposits and in combi- 

 nation with cartilage and fibrous tissue occasionally in the lungs 

 (cowO, peritoneum and mesentery (cow, hog, dog), upon and 

 within the udder (cow% dog), testicles (horse), in the vitreous 

 humor of the e}'e (horse), and in the right cardiac auricle of the 

 horse. The attempt to explain the origin of these bone forma- 



Fig. 96. 

 Section of above osteoma of horn process. 



tions must rest with the assumption of the possibility of a meta- 

 plasia of fibrillar connective tissue into a calcified matrix, with 

 transformation of'the connective tissue corpuscles into bone cor- 

 puscles. 



