TUMORS. 477 



Fatty degeneration is often met with, especially in malignant 

 tumors, and, if a larger portion be invaded, results in the forma- 

 tion of the " reticulum " of older pathologists. Fatty degenera- 

 tion rarely appears throughout the entire tumor, but if this 

 happens, subsequent calcification and ossification ensue, rendering 

 the growth harmless. Cheesy metamorphosis is sometimes ob- 

 served with the production of a yellow, friable, half -dry, shriveled 

 mass, as seen in tubercle ; this process is, as a rule, limited, and 

 has no influence upon the further growth of the tumor. 



Mucous and colloid degeneration is a rather common occur- 

 rence, especially in adenoma an<J, cancer, and results in the for- 

 mation of cysts. Upon this metamorphosis rests the formation 

 of colloid and cystic cancer, and that of cysts in general. These 

 will be dwelt upon later. Waxy degeneration is not infrequently 

 found. All these metamorphoses lessen in a great degree the 

 malignity of a tumor. 



Hyaline or hyaloid degeneration results in the transformation 

 of the tissue elements into a transparent mass, extremely indif- 

 ferent to the action of acids and alkalies, and is of rare occur- 

 rence; it invades the tumor partially only and has no influence 

 upon its general growth. The enlarged and concentrically stri- 

 ated elements of the tumor sometimes exhibit peculiar sprouts 

 and pedunculated formations the " gems' 7 of Rokitansky and 

 the " physalids n of Virchow. The intimate nature of these proc- 

 esses is far from being understood. 



Calcareous deposition is observed in fatty masses, transforming 

 them into a dry, brittle, cement-like substance ; or it produces an 

 incrustation of waxy or hyaloid corpuscles for instance, in the 

 psammoma ; or it invades all epithelia of cancer simultaneously, 

 rendering the tumor innocuous. Large masses of connective 

 tissue may become calcified, especially in fibrous tumors grown 

 from the periosteum. Ossification, with the production of more 

 or less irregular systems of lamellae, containing central medullary 

 spaces and well-defined bone-corpuscles, occurs in a limited num- 

 ber of tumors fibroma, chondroma, myeloma, and so-called 

 osseous cancer. In most instances this process represents an only 

 incomplete mode of healing. 



Classification. For over seven years I have taught in my 

 laboratory a systematic division of tumors given in outlines in 

 my essay, published in 1879, above quoted. If we bear in mind 

 that an exact definition and classification is impossible that 

 there are innumerable transitions of one kind of tumor into 



