732 DR ALEXANDER BRUCE AND DR JAMES W. DAWSON ON 
cutis may also be irregularly thickened and studded with fibromatous nodules, in which 
the perineurium of the affected nerve bundles may, however, not be defined from the 
surrounding connective tissue. 
(c) Cutaneous neurofibroma (molluscum fibrosum) are of the nature of soft fibroma 
related to the terminal filaments of cutaneous nerves, and may be distributed over the 
whole body. 
(2d) Elephantiasis neuromatosa.—In addition to the fibromatosis of cutaneous nerves 
there is here a pronounced and diffuse overgrowth of the connective tissue of the skin 
and subcutaneous tissue, 7.e. an extension of the fibromatosis from the endoneurial 
connective tissue of cutaneous nerves to the tissue surrounding them. 
(e) Pigmentations of skin associated with neurofibromatosis. 
(f) Secondary malignant sarcoma, 7.e. a sarcomatous transformation of one or other 
of the forms of neurofibromatosis. 
THOMSON presents neurofibromatosis as a disease which, while confined to the peri- 
pheral nervous system, may be distributed throughout its whole extent, viz. the 
cerebro-spinal nerves, the sympathetic nerves, and the nerve terminations in the skin. 
These may be regarded as constituting one organ alike from developmental, structural, 
and functional points of view. He agrees with Gotpman, Bruns, and others that the 
condition is a form of gigantism or elephantiasis of the connective tissue elements of 
the peripheral nervous system, and that it appears to be a developmental disease dating 
from intra-uterine life. THoMsoN significantly adds that a more accurate knowledge of 
the development of the peripheral nervous system may shed some light on the origin 
of neurofibromatosis. 
During the past ten years careful research into the embryogenesis and regeneration 
of nerve fibres has given an altogether new view to the structure of tumours related to 
nerves, whether circumscribed or diffuse. 
Durante (1906) has related this new view to his conception of the multicellular 
structure of the nerve fibres. According to it the tumours represent true neuromata, 
and owe their origin to a cellular regression of the segmental cells of the nerve fibre. 
The differentiated substance of the interannular segment of the nerve fibres disappears, 
and the undifferentiated vegetative protoplasm increases in quantity; and, with a 
simultaneous proliferation of the nuclei, forms homogeneous tubes or individualises into 
spindle-shaped cells. ‘These cells may again fuse and form protoplasmic bands which 
have a great similarity to Remak’s fibres, and must be looked upon as young nerve 
fibres. In proportion as they persist at the stage of undifferentiated protoplasm or 
differentiate further to elaborate myelin, they represent amyelinated or myelinated 
neuroma. If the new elements that have arisen through cellular regression remain as 
individual cells and proliferate further, then there arises an embryonal malignant form 
of neuroma, which in appearance resembles a sarcoma, and might be, in contrast to the 
others, termed a cellular neuroma. Again, the new-formed elements might undergo 
various metamorphoses, ¢.g. atrophy, and take the appearance of connective tissue, or 
