530 



LECTCRE XX. 



perhaps the dermoid growths which produce hairs, teeth, 

 and sebaceous glands, and so frequently occur in the ovary 

 all these are formations in which there is a pathological 

 production of epithelial cells, but they constitute a gradu- 

 ated series of different kinds, which extend from those 

 which are entirely local, and, in the usual meaning of the 

 word, perfectly benignant, to the extremest malignity. 

 The mere form of the cells which compose a structure, is 

 of no decisive value. Cancer is not malignant because 

 it contains heterologous cells, nor cancroid benignant 

 because its cells are homologous they are both malig- 

 nant, and their malignity only differs in degree. 



The forms which yield dry, juiceless masses, are rela- 

 tively benignant. Those which produce succulent tissues 

 have always more or less a malignant character (p. 251). 

 The pearly tumour, for example, yields perfectly dry epi- 

 thelial masses, almost without a trace of moisture, and it 

 only infects locally. Cancroid remains for a very long 



FIG. 143. 



Fig. 148. Section through a cancroid of the orbit. Large epidermic globules 

 (pearls), Inminated after the manner of an onion, in a closely packed mass of cells, 

 which have partly the character of epidermis, partly that of rete Malpighii. 150 



