XIII. 



TUMOKS.^ 



DEFINITION. Tumors are morbid outgrowths of living tis- 

 sues. An exact definition is impossible; and Virchowt 

 himself has said : "If we were to torture a person to the last 

 degree of endurance, he would still be unable to tell what tumors 

 really are." The same author extends the limits of these forma- 

 tions to such a degree that he speaks of " tumors of extravasation 

 and of retention" that is, tumors which have arisen from a col- 

 lection of extravasated blood, or an exudate, or physiological 

 secretions. He furthermore dwells upon " granulation tumors," 

 which, in the present view, are considered products of inflamma- 

 tion. We shall confine the idea of tumors to those formations 

 only which, by pathologists, are termed " neoplasma " or " pseudo- 

 plasma," which originate without marked inflammatory symp- 

 toms, and terminate without a typical end; while the inflammatory 

 process is completed by the production of a cicatrix. The best 

 definition is undoubtedly that of A. Liicke, who says : " A tumor 

 is a growth produced ~by new formation of tissue, without a physio- 

 logical termination." 



* This chapter aims to present the outlines of oncology only. Since the 

 establishment of my laboratory in New-York, over seven years ago, I have 

 been generously supplied with specimens of tumors by a large number of 

 physicians. I desire to return my thanks to them, and must specially mention 

 by name Dr. H. B. Sands, for his kindness in this and other respects in sup- 

 port of my laboratory. 



t " Die krankhaften Geschwiilste." Berlin, 1863-67. The most exhaust- 

 ive treaty on tumors, but unfortunately not completed. 





