Ranson, Fibers in Lesions of the Brain, IgI 
section of a part of a hemisphere was practiced, the place of 
the excised tissue was taken by a soft reddish mass composed 
of nerve fibers, nerve cells and neuroglia. These statements 
would be more convincing if we could be sure that no nerve 
cells had survived the degenerative processes in the immediate 
vicinity of the foreign body; and that when a piece of the 
brain was excised, the margins of the wound did not become 
approximated, at the same time undergoing partial degenera- 
tion with glia formation, and thus giving rise to the soft red- 
dish mass described as filling the wound. 
Analogous to TEDESCHI’s observations after excision of 
part of a dog’s cortex, are the results of Virzou (33) (1897) 
after ablation of the occipital lobes of a young monkey. 
About two years after the first operation he opened the skull 
again and in the second operation removed the tissue which 
was found occupying the position of the former occipital lobes. 
This mass, which he regarded as new-formed, was much the 
same in structure as normal brain tissue; but since it was re- 
moved under limitations imposed by the operation, neither its 
relation to the rest of the brain, nor its gross appearance was 
adequately described. Nor do his figures show the transition 
between the new-formed and the normal brain substance. For 
this reason one cannot be sure that it does not represent 
uninjured tissue displaced posteriorly. Whatever may be 
thought of the physiological evidence brought forward in this 
case, the anatomical evidence seems to be very inconclusive. 
With regard to the mitotic division of nerve cells, TE- 
DESCHI has received better support. FRIEDMANN (13) (1889) 
has observed that, when the irritation of the cortex is suffi- 
ciently severe and at the same time perfectly aseptic, prolifera- 
tion of the ganglion cells may occur. Monpino (25) (1886) 
and Coen (8) (1887) obtained similar results after puncturing 
the brains of guinea-pigs and rabbits with red hot needles. 
Coen, however, found that the new-formed ganglion cells soon 
disappeared, and the final cicatrix contained neither nerve 
fibers nor nerve cells. 
While most of the investigators who have worked in this 
