736 DR ALEXANDER BRUCE AND DR JAMES W. DAWSON ON 
He thinks that the presence of the completely naked axis-cylinders, found by BENEKE 
and OBERNDORFER, argues against the possibility of the origin of the nerve fibre from 
the sheath of Schwann cells. In both axis-cylinder and medullated sheath numerous 
degenerative phenomena could be ascertained, which showed a definite dependence 
upon the degree of degeneration of the ganglion cells. Wrcr.in therefore finds no 
reason to depart from the generally accepted view that the nerve fibres had arisen from 
the ganglion cells. He relates the starting-point of ganglio-neuroma to cell displace- 
ment in early embryonal life. 
Homer Wricut (1910) has drawn attention to a group of tumours which, at first 
sight, are apt to be mistaken for round-celled alveolar sarcomata. The tumour tissue 
consists of cells and fibrils. The cells have the same morphology as the cells from 
which the sympathetic nervous system develops: they are generally small, with round, 
deeply-staining nuclei and little cytoplasm, or they may be pyriform with the 
cytoplasm prolonged into filamentous processes. The fibrils are often of considerable 
length: they do not stain like neuroglia or connective tissue fibrils, and are like the 
fibrils occurring in the anlage of the sympathetic nervous system. The fibrils may 
be arranged in bundles or ball-like formations of cells may occur, enclosing a mesh- 
work of fibrils and filamentous processes of the cells. ‘The tumour tissue, therefore, 
presents the appearance of being composed of aggregations of more or less a-typical 
embryonic sympathetic ganglia bound together by connective tissue stroma. The 
essential cells of the tumour are considered to be more or less undifferentiated nerve 
cells or neurocytes or neuroblasts, and hence the terms neurocytoma or neuroblastoma 
applied to the tumours. The occurrence in a variety of situations, and especially in 
the adrenal, is explained by the migration of undifferentiated nerve cells from the 
embryonic central nervous system to form the nerves and ganglia of the sympathetic 
nervous system. 
(b) Corcumseribed Newroma. 
BaRILE (1910) records the careful microscopic examination of an egg-shaped tumour 
of the forearm. At the operation the tumour, which was 5 x 4 cm. in size, was found 
surrounded by a capsule, but at both poles seemed to have fibres of the radial nerve 
attached to it. ‘The tumour consisted entirely of bundles of nerve fibres with scarcely 
any interstitial tissue, and was without ganglion cells, therefore a true fibrillated neuroma. 
In the periphery of the tumour the bundles had a parallel course, but in the central 
parts the bundles interlaced in very varied directions. The fibres are only in part 
myelinated, and these are distinguished from normal adult fibres by their delicacy. 
They are found mixed with some that have an axis-cylinder and nucleus but no myelin 
sheath, and with others that correspond to the plasmodial bands of Durawnrs, in which 
are present filaments that take the axis-cylinder stain. In addition, there are also 
