TUMORS. 



279 



into there may be a creaking sound similar to that produced in 

 cutting a tendon. They have little or no tendency to peripheral 

 infiltration but grow by central or interstitial expansion, mechan- 

 ically pushing the contacting tissue aside. 



If the tumor has degenerated or become necrotic quite a dif- 

 ferent picture than the above will be seen. It may be a mass of 

 mucus as a result of mucoid degeneration. It may contain 

 necrotic areas or the entire tumor may undergo necrosis, the 

 necrotic tissue becoming lic[uified, coagulated, caseated or calci- 

 fied. Hemorrhage into the tumor tissue may give it a mottled 

 appearance. The hemorrhagic spots may be red, yellowish-red 

 or greenish-red, depending upon the changes in tlfe hemoglobin. 



Microscopically, the tumor tissue appears as white fibrous 

 connective tissue, being composed of cells and a white fibrous 

 intercellular substance. 



^'BoJiw^-- 



j-lg 140— Spction of a hard Fibroma showing: 1. Transverse section o£ 

 bundles of Fibres; 2. Longitudinal section of bundles. 



The cells are usually few in number, are flat and have a flat, 

 oval nucleus. Cells are more prevalent in the rapidly growing 

 tumors. The arrangement of the fibres varies and is the deter- 

 mining factor of the denseness of the tumor. 



A hard fibroma is made up of bundles of fibres extending in 



