Nov., 1917] Tumors in Dogs 5 



cells at the point of origin of this tumor and since there is a 

 close association of reticular fibrils with the giant cells as well as 

 with the tumor cells, it seems indicated that the giant cells in 

 this tumor are produced by the fusion of tumor cells and for 

 this reason present a tendency to differentiate as do the cells 

 from which the tumor arose. 



That this is not the only mode of origin of fusion giant 

 cells seen in new growths is apparent from the description of 

 the origin of such cells by Whitman ('14). An examination of 

 the specimens of giant cell sarcoma in the Museum of Pathology 

 at the Ohio State University has shown that some of the giant 

 cells originate from endothelium. This agrees with Mallory. 

 It is the behavior of the more undifferentiated cells that deter- 

 mines the clinical course of the growth of the tumor. Giant 

 cells such as are seen in this specimen become, therefore, of 

 secondary interest for they do not determine the classification 

 of the tumor as a fibroblastoma. They, however, indicate 

 that the tumor is relatively benign. This is in agreement with 

 Ivy's conception ('15) that the presence of these giant cells 

 indicates that the tumor is probably not malignant. 



SUMMARY. 



This tumor arising in the alveolar process of the upper jaw 

 of a dog is a rather slowly growing fibroblastoma, which con- 

 tains giant cells. 



By the application of the Maresch-Bielskowsky technique 

 of impregnating with silver it is established that the tumor cells 

 possess black argentiferous fibrils and that the giant cells 

 present in this tumor are produced by the fusion of cells which 

 also have these same fibrils in close association with them, 



BIBLIOGRAPHY. 



1. Ferguson, 1912. The Application of the Silver Impregnation Method of 



Bielskowsky to Reticular and Other Connective Tissues. Am. Jour. Anat. 

 Vol. XII, p. 277. 



2. Fohner. (Cited by Wolff). 



3. Ivy, 191.5. Mesothelial Tumors of the Jaws. Jour. Am. Med. Assn. LXIV, 40. 



4. Mallory, 1911. Giant Cell Sarcoma. Jour. Med. Res. Vol. XIX, p. 463. 



5. Means & Forman, 1915. Precancerous Conditions of Face and Mouth. Dental 



Summary, XXXV, p. 945. 



6. Means & Forman, 1916. Epulis. Dental Summary. XXXVI, p. 494. 



7. Means & Forman, 1917. A Clinico-Pathologic Study of Early Malignant Con- 



ditions of Face and Mouth. Jour. Am. Med. Assn' Jan. 20, 1917. p. 180. 



8. Warren, James H., 1917. The Giant Cell in Tuberculosis. Jour. Med. Res. 



Vol. XXXVI. No. 2. May, 1917. 



9. Whitman, 1914. Giant Cell Endothelioma of the Gums. Jour. Med. Res. 



Vol. XXIV, p. 465. 



10. Wolff, 1913. Lehre von der Krebs Krankheit, Jena. 1913. 



