Classification of Tmnors. 327 



and adaptation of the cells and matrix of tumors. The cells 

 frequently do not attain the same size as the mother cells or 

 may be larger than the latter ; cellular division takes place some- 

 times as a direct process, sometimes indirectly with mitotic 

 changes. The mitotic figures, which are likely to be found in 

 great numbers, especially in rapidly growing tumors, and the 

 process of cellular division often show irregularities pointing to 

 a pathological disturbance of the process. The chromatin fila- 

 ments derived from the chromatin skein (chromatosomes) may 

 be too numerous or asNinmetrical ; or there may be found giant 

 mitoses, karyokinetic figures in multipolar arrangement, arranged 

 about a number of attraction centres (centrosomes), or giant 

 cells. The cells may also, as stated by Ribbert, exhibit altera- 

 tions which may be regarded as regressive in character, as a 

 return to an embryonic state in which there is but little evidence of 

 differentiation ; or they may really be embryonic cells whose 

 power of forming normally functionating organs has been lost 

 (a change designated by Hansemann by the term Anaplasia) . 



The cellular type and the character of the tissue of the growth 

 furnish the basis for nomenclature of tumors. Many tumors are 

 made up of but a single kind of tissue, as fibrous connective 

 tissue, fat tissue or cartilage, or at least mainly of one type (the 

 accompanying bloodvessels are not regarded as a special form of 

 tissue but as essential constituents of any form) ; such growths 

 are called simple autohlastomata. Others, no less numerous, 

 contain two or more tissues, as is obviously required in epithelial 

 new growths because epithelium always requires a connective 

 tissue substructure, and as is likely to occur, too, in other tumors 

 from the mixture of the various forms of connective tissue, as 

 cartilage, bone or fat ; we therefore recognize as a second group, 

 the compound autohlastomata or mixed tumors. 



It should be recognized, too, that tumors as independent devel- 

 opments, although relying on the animal body for their nutri- 

 tion, yet having their own blood vessels and carrying on a 

 separate metabolism, are subject to all the pathological processes 

 which may affect the normal tissues of the body. A tumor may 

 become the seat of passive hyperaemia, of inflammatory reaction ; 

 and any kind of degeneration and necrosis may occur in the 

 tumor structure. Tumors are sometimes subject to traumatic 

 influences from without (strangulation, wrenching, penetration 

 by foreign bodies or bacteria) which may occasion tissue 

 changes; sometimes the conditions of nutrition become so un- 



