300 OPERATIVE SURGERY. 



injury to a part may be followed by tumor formation, not merely 

 a simple swelling of the tissue resulting from inflammation con- 

 sequent to the injury, but by the formation of new adventitious^ 

 tissue growth; but in the human family, and also in some of the 

 herbivora we find heredity undoubtedly is a vital point in the 

 situation. Then again, Cohnheim's theory of the misplacement 

 of embryonal cells undoubtedly is frequently correct. And of 

 late years parasitic origin appears to be receiving much consid- 

 eration at the hands of investigators. 



Cystic tumors are enlargements containing a .fluid-like 

 serum, and, according to Paget, originate by three different 

 methods : Either by enlargement and fusion of the spaces of the 

 connective or other tissues, the fluids accumulating in these 

 spaces, causing the tissues to become rarefied, the dividing septa 

 of the spaces becoming broken down till a sac or cyst is formt'(l, 

 the outside boundaries of which continue to secrete fluid which 

 accumulates in and press out the walls of the sac, so enlarging it ; 

 or by dilatation and growth of natural ducts; or by rapid growth 

 of new elementary structures, which is the form occurring as 

 goitre, in the thyroid bodies of young animals, lambs frequently 

 being oo affected. 



CrcatmeTit. 



Treatment of tumors consists in their early extirpation by 

 means of the knife or destruction of the cell elements with strong 

 caustics, etc. The ram is at times affected with a tumor of the 

 penis, which appears to belong to the carcinomata, and which 

 necessitates early removal by knife or ligature. 



For the removal of a malignant growth to be successful 

 every particle of the foreign tissue must be removed, it being a 

 safe plan to dissect out some of the normal tissue contiguous to 

 the growth, and so guard against the possibility of leaving be- 

 hind any of the adventitious tissue. Yet even in many instances 

 where the growtli is malignant, it tends after removal, to recur 



