478 TUMORS. 



another, my mode of division will be found the simplest and most 

 satisfactory, so far as my experience, which is based upon the ex- 

 amination of many hundred tumors, permits a definite conclusion. 

 The system is strictly histological. 



According to the four main varieties of basis-substance of 

 connective tissue the myxomatous, fibrous, chondrogenous, and 

 osseous I arrange the benign connective-tissue tumors proper 

 as follows : 



1. Myxoma. 



2. Fibroma. 



3. Chondroma. 



4. Osteoma. 



The embryonal or medullary condition of the connective 

 tissue furnishes the well-known malignant type of : 



5. Myeloma (sarcoma). 



The combination of connective tissue with fat, with a large 

 amount of blood-vessels, with muscles and nerves, provides four 

 other benign varieties : 



6. Lipoma. 



I. Angioma. 



8. Myoma. 



9. Neuroma. 



Any one of the eight benign types may be combined with the 

 type of myeloma, and then they are termed : myxo-, fibro-, chon- 

 dro-, osteo-, lipo-, angio-, myo-, neuro-myeloma. This combination 

 shows that the tumor tends toward malignity. 



The combination of connective with epithelial tissue results 

 in the production of two varieties of benign tumors, in which 

 the epithelium furnishes either the outer investment or produces 

 glandular formations : 



10. Papilloma. 



II. Adenoma. 



The great majority of cysts are secondary formations of 

 adenoma, and may, therefore, be considered under the head of 

 adenoma. Adenoma may be constructed of myxomatous or 

 fibrous connective tissue : Myxo- and fibro-adenoma ; or it may 

 be built up by connective tissue in a medullary condition : Adeno- 

 myeloma. 



The combination of connective tissue with epithelia not form- 

 ing glands, but either having the appearance of pegs, nests, or 

 plexuses, or filling alveoli, surrounded by connective tissue, gives 

 the malignant type of : 



