360 Tumors. 



a grayish-red, seniitransparent appearance and usually extends 

 along many adjacent nerves as a nerve plexus, giving rise to 

 an extensively intertwining growth { plcxiform or vine-like neuro- 

 fibroma). Tumors of this kind have been observed, especially in 

 cattle, involving the brachial plexus and the dorsal, costal and 

 sternal nerves (Ostertag, Alorot, Blanc, author's personal obser- 

 vation), and producing in these structures hundreds of nodular 

 thickenings. Morot counted in one case thirteen hundred and 

 fifteen neuromyxomata in an old cow and traced them even to 

 the nerves of the pharynx and heart. Leisering observed similar 

 growths in a horse with extensive involvement of a number of 

 nerve trunks. 



An embryonic developmental disturbance of unknown nature 

 has been regarded as the basic factor for the neurofibromata and 

 neuromata observed in man, because the growths have been met 

 as congenital and inherited faults. 



Glioma or ncuro glioma, the tumor of nervous connective tis- 

 sue substance, is produced by proliferation of the glia cells of the 

 central nervous system or the granular layer of the retina of the 

 eye, and occurs primarily only in these two positions. In animals 

 it has been recognized with certainty but twice, once by Gratia 

 in a dog's brain (ganglion Gasseri) and again by Piana in the 

 spinal cord of a dog, in both instances causing palsies from 

 pressure upon the central nervous substance and the emerging 

 trunks. 



The gliomata of the human brain are usually embedded in 

 the brain tissue without sharp definition from the latter and are 

 so merged with it that they are only recognizable as diffuse 

 grayish or reddish firm areas. They are made up of protoplasmic 

 cells with numerous fibrils projecting in a radiating fashion from 

 all sides of the cell (spider cells, astrocytes) ; and in this fibrillar 

 meshwork there are in some instances also present polymor- 

 phous sarcomatous or ganglionic cells, and epithelial inclusions 

 may be observed (spaces lined with cylindrical epithelium). This 

 last feature and the occurrence of these growths in newly born 

 children confirm the belief that disturbances of development of 

 the cerebral vesicles are the basis of these neuroglia growths, for 

 example isolation of offshoots from parts covered by ependyma 

 (perhaps, too, transformation of the glia cells to embryonic cel- 

 lular type, the glia tissue being originally an epithelial tissue 

 differentiated into a supporting material). 



