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almost entirely of tlie tissues of which the body is com- 

 posed, generally of some form of connective tissue ; such as 

 neuroglia, bone, cartilage, white fibrous tissue, or adipose 

 tissue. 



2. The Sarcomatous tumors are composed largely of 

 embryonic tissues, which may, in some cases, reach a partial 

 development, but the growth of the tissues always stops 

 before reaching the highest stage of development. 



3. Carcinomas or Cancerous tumors are those in which 

 any of the elementary tissues of the body may be present, 

 but these tissues are present usually in an erratic manner. 



Since the morbid skin growths have been classified as 

 tumors, the question arises, to which of the above three 

 groups do the skin tumors belong? 



Some writers classify similar tumors under the head of 

 fibromas (fibrous tumors) ; others take a stand half way be- 

 tween the first and second groups and call them sarco- 

 fibromas. Evidently, it is rather difficult to distinguish 

 between a young or embryonal fibroma and a spindle-celled 

 sarcoma. A spindle-celled sarcoma is composed of young 

 or embryonal fibrous connective tissue cells ; the embryonal 

 or young fibroma contains young fibrous connective tissue 

 cells very like those found in a spindle-celled sarcoma. 

 However, after the fibroma has reached a greater degree of 

 maturity, it is comparatively easy to distinguish it from a 

 sarcoma. 



In none of the cases, which I have studied with the micro- 

 scope, have I found anything characteristic of the sarcoma ; 

 but in every case, as I hope to show by the accompanying 

 plates, I have found them to be distinctly fibromatous, 

 fibrous tumors. 



The fibromas are divided into the hard and soft variety. 



The soft fibroma is nothing more or less than young con- 

 nective tissue ; the tumor contains more cells than fibres, 

 and its cellular elements are not so highly developed as in 

 the hard fibroma. The soft fibroma bears a greater simi- 

 larity to the sarcoma than the hard fibroma. 



