264 THE MICROSCOPIST. 



neighboring lymphatic glands, and of reproducing them- 

 selves in distant organs. It is not confined to carcinomas 

 or cancers, since many sarcomas are just as malignant. 



Pathological new formations are subject to retrogressive 

 changes similar to those of physiological tissues. Deficient 

 supply of blood is followed by fatty degeneration, with its 

 varied terminations, softening, caseation, and calcifica- 

 tion. Pigmentary, colloid, and mucoid degeneration may 

 also occur, or inflammation. In addition, one form of 

 tissue may be transformed into another, especially of the 

 same group, as of connective tissue elements. Thus can- 

 cers may form in cicatrices and tumors of various kinds, 

 sarcomas in fibromas, etc. 



Pathological new formations have been variously classi- 

 fied. For convenience of the student we divide them as 

 follows: 



1. Pathological formation of cells 



2. Pathological growth of higher animal tissues. 



3. Pathological growths of connective tissue origin. 



4. Pathological growths of epithelial origin. 



I. NEW FORMATION OF PATHOLOGICAL CELLS. 



We have already stated that proliferating cells, either 

 tissue-cells or wandering leucocytes, produce abnormally, 

 first, an embryonic or indifferent tissue. This seems iden- 

 tical with granulation tissue (page 262). From it various 

 new growths proceed. The cells multiply as in normal 

 tissues, by division, budding, or endogenous formation 

 (page 125). Cell division affects the entire cell nucleus, 

 nucleolus, and bioplasm. It is generally accomplished 

 quickly, judging from experiments on the warm stage of 

 the microscope (page 42). Budding is a variety of self- 

 division, in which a small portion of bioplasm is protruded 

 and separated so as to become an independent cell. In 

 exogenous cell formation the nucleus, after previous di- 

 vision of the nucleolus, divides into two or more nuclei. 



