266 THE MICROSCOPIST. 



etc., may any of them become points of departure for 

 pathological new formations. The youngest formed, or 

 embryonic cells, may be developed like the tissues of the 

 embryo, may become connective tissue cells, bone-corpus- 

 cles, muscle-fibres, and, according to some, true epithe- 

 lium, etc., or cancer-cells, sarcoma-cells, etc. The cells, 

 however, which rise from various tissues usually give 

 origin to definite new formations. Thus epithelial forma- 

 tions arise from epithelial tissue ; connective tissue forms 

 from connective tissue, etc. 



II. PATHOLOGICAL GROWTHS OF HIGHER ANIMAL TISSUES. 



1. Muscular Tissue. a. Striated. Virehow, and after 

 him Billroth and others, have shown that the elements 

 of the more highly organized tissues, as the nervous and 

 muscular, are rarely imitated pathologically. 



Systematic writers term striated muscular tumors rhab- 

 domyoma, or true myoma. The few instances referred to 

 consist of a few fibres mixed with other tissues in cystic 

 tumors of the ovary, testicle, etc. 



b. Smooth muscular-fibre tumors, or leiomyoma, fibroid, 

 in the narrower sense, occurring most frequently in the 

 body of the uterus, either as submucous, intramural, or 

 subperitoneal tumors, are so similar in their elements to 

 the ordinary fibroma as not to be distinguished from it. 



2. Nervous Tissue. The term neuroma is applied to a 

 fibrous tumor on a nerve. It is quite doubtful if the term 

 is applicable. The cases recorded are small, roundish, 

 hard tumors, occurring in the course of nerves, and nod- 

 ules on nerves at the end of amputation stumps. They 

 consist, however, of increased vascular connective tissue 

 separating the nerve-fibres. Rindfleisch refers to a case 

 which he deems a true neuroma. He says it is the first 

 example of a genuine one, yet states that it may be a 

 hypertrophied ganglion of the sympathetic. 



