346 HISTOLOGY OF THE MORBID PROCESSES. 



tissue they most closely resemble and the suffix " oma." Thus, 

 a fibroma is a tumor consisting essentially of fibrous tissue i. e., 

 connective-tissue cells with a fibrous intercellular substance even 

 if the arrangement of the tissue-elements is not quite like that 

 of normal fibrous tissue. A myoma is a tumor composed of mus- 

 cular tissue, with only so much admixture of fibrous tissue as would 

 be comparable with that found in masses of normal muscle. But 

 as there -are smooth and striated muscular tissues, so there are 

 leiomyomata and rhabdomyomata. When a tumor contains two 

 varieties of elementary tissue in such proportions that neither can 

 be considered as subsidiary to the other, it receives a compound 

 name, in which the most prominent or important constituent tis- 

 sue is placed last, being qualified by the name of the less impor- 

 tant tissue. Thus there are myofibromata, in which the fibrous tissue 

 is more prominent than the muscular tissue ; and fibromyomata, in 

 which the muscular tissue predominates. In like manner three or 

 more tissues may be designated as forming a tumor by such names 

 as osteochondrofibroma, myxochondrofibroma, etc., implying that 

 the growths are composed of fibrous tissue with an admixture of 

 cartilage and bone, or cartilage and mucous tissue, etc. 



The problem of classification is not so simple when we take up 

 the consideration of tumors less closely resembling the normal 

 tissues that are found in the adult body. Those tumors which are 

 akin to embryonic tissues still retain names that have come down 

 from earlier times, and which were conferred on them because 

 of some characteristic visible to the unaided eye. Those of con- 

 nective-tissue origin are called sarcomata (singular, sarcoma), which 

 means tumors of fleshy nature ; and those containing tissues derived 

 from epithelium are called carcinomata, or cancers, because by 

 virtue of their infiltration of the surrounding tissues they possess 

 a fanciful resemblance to a crab. The terms sarcoma and carcinoma 

 have, in the course of time, become more defined, and are now re- 

 stricted to certain well-marked types of structure. The carcinomata 

 are composed of fibrous tissue and epithelium, the one derived orig- 

 inally from the mesoderm, the other from either the epiderm or hypo- 

 derm. In this dual origin they resemble the viscera of the body, 

 and may, therefore, be regarded as among the simpler members of 

 the group of organoid tumors. The most complex members of that 

 group are the " teratomata," which contain structures simulating 

 hair, teeth, bones, etc., arranged without definite order, and often 



