498 



TUMORS. 



these haematoblasts, before their development into red blood- 

 corpuscles, arise the pigment clusters. The process can be best 

 studied at the border of melanotic myeloma of the choroid in the 

 region of the vitreous body. Here the haematoblasts originate in 

 the middle of the vitreous body, being characterized by a globular 

 shape, luster, distinct yellow color, and their small size, as com- 

 pared with fully developed red blood-corpuscles, for which they 



often are taken. How far the 

 haematoblasts participate in 

 the new formation of the my- 

 eloma elements I was unable 

 to ascertain ; but unquestion- 

 ably they are the source of 

 pigment in melanotic myelo- 

 ma. (See Fig. 198.) 



Combinations of Myeloma. 

 ^Myeloma may combine with 

 any variety of connective tis- 

 sue- and epithelial tumors, 

 which means that a portion 

 of the tumor possesses fully 

 developed basis -substance, 

 while another portion has 

 but little or lacks it entirely. 

 A tumor with originally well- 

 FIG. 197.-FIBRO-MYELOMA, WITH MUL- develop ed basis - substance 



TINUCLEAR PLASTIDS. FROM THE in i , 



LOWER JAW OF A YOUNG MAN. ma ^ gradually change its 



character, and in the por- 

 tions of later growth be with- 

 out basis-substance. With this 

 failure in the production of 

 basis-substance a more rapid growth of the tumor ensues, and it 

 assumes a more malignant type. As before mentioned, such 

 tumors are clinically considered "dubious" in their nature, 

 although some of them are either of a marked malignant char- 

 acter, or become so in a relatively short time. According to our 

 nomenclature, the various combinations of these tumors are 

 termed as follows : 



(a) Mbro-myeloma, the "fibroplastic" tumor, or " recurrent 

 fibroma" of older pathologists. It consists of bundles of fibrous 

 connective tissue, between which are large numbers of usually 

 globular elements ; or the tumor originates from fibrous tissue, 



M, group of medullary corpuscles approach- 

 ing the stage of indifference ; G, multinuclear 

 plastid, so-called giant-cell. Magnified 600 

 diameters. 



