544 TUMORS. 



thelia f. i., the so-called osteoblasts, arising from medullary elements. In 

 both the epithelial and connective-tissue formations, in certain stages of their 

 development, we meet with multinuclear bioplasson masses, in which in later 

 stages either cement-substance or basis-substance makes its appearance. So 

 far as the origin of different tissue forms is concerned, there is indeed a 

 marked similarity between them all. 



I maintain that in development of carcinoma epithelial formations appear in the 

 connective tissue which are independent of former glandular formations. The 

 proofs for this assertion are the closed spindle-shaped spaces of the connective 

 tissue, which contain epithelia, and the epithelial formations which are traversed by 

 branching elastic fibers. 



The closed spaces of the connective tissue were supposed to be lymph- 

 spaces, the endothelium of which had been transformed into cancer elements, 

 or lymph-spaces into which cancer elements had immigrated. The first 

 mentioned concept of authors I need not contradict, for the endothelium is 

 admitted to be a formation of connective tissue. The second assertion lacks 

 foundation, for epithelia themselves do not migrate, and the assumption of a 

 transformation of indifferent migrating corpuscles into cancer epithelia does 

 not assist us in the explanation of the origin of cancer. 



My second proof is, I think, a still stronger one. It is that elastic fibers 

 have never been observed in epithelial tissue, and, where they are present, 

 they prove rather the origin of the epithelia from former connective tissue, 

 whose territories are often bounded by elastic substance. 



I, therefore, consider the epithelial formations in the midst of connective 

 tissue as the result of a rejuvenescence of the latter, such as we observe in 

 the inflammatory process. Under anomalous conditions the connective tissue 

 returns to its medullary stage, which in sarcomatous growths remains sta- 

 tionary. If, on the contrary, the development from the medullary stage 

 proceeds to the production of cement-substance, the medullary corpuscles 

 assume the character of epithelia. The blood-vessels and their districts of 

 nutrition may also have an influence on this process of development of epi- 

 thelia, though the influence cannot be determined by observation, any more 

 than an explanation is possible where the infection of cancer is located, 

 which is transportable to neighboring lymphatics and to different and remote 

 organs. 



Virchow's assertion that in certain conditions epithelium arises from con- 

 nective tissue I consider to be correct, and I would widen this assertion by 

 adding that it is not the connective-tissue corpuscles alone which furnish new 

 elements, but it is the totality of living matter contained in the basis-sub- 

 stance which participates in the production of new epithelial elements. 



Local Origin and Transmission. Malignant tumors frequently 

 arise from long-continued irritation or from traumatic inflam- 

 mation. Cancerous tumors, especially, can be traced to such a 

 source. After a number of years warts on the face, owing, perhaps, 

 to some slight injuries inflicted in washing, may ulcerate and 

 assume the character of cancer. In smokers, cancer of the lips 

 is often produced by the long-continued friction of jagged, bitten 

 pipe-stems. Cancer of the tongue often arises from ulcers pro- 



