Bastian, on the so-called Pacchionian Bodies, 87 
tions in comiection witli the skull and membranes of the 
brain — occasionally in great numbers as well as much en- 
larged — it is a matter of some interest to know in Avhat situa- 
tions they may be found;, how they come to occupy these 
positions, what is their precise histological structure, whether 
they are normal or abnormal growths, and, if the latter, what 
is their pathological significance. 
In text-books they are principally referred to as existing on 
the surface of the dura mater, on one or both sides of the 
middle line and subjacent longitudinal sinus, and causing 
more or less marked depressions in the corresponding region 
of the skull. It is also generally stated, however, that their 
presence is uncertain, that they are most frequently met with 
in persons dying at an advanced age, and that they are occa- 
sionally seen in the longitudinal sinus as well as on the 
arachnoid along the edges of the great longitudinal fissure 
separating the cerebral hemispheres ; whilst, if anything at all 
is said concerning their seat of origin, this is represented to 
be in the pia mater beneath the arachnoid. Such a view as 
to their origin was held by Cruvelhier,"^^ Andral,t and the late 
Dr. Todd,J and seems to have been adopted by other English 
anatomists, notwithstanding the observations of Luschka,§ 
who in 1852 clearly pointed out that they invariably arose 
from, and were direct continuations of the arachnoid mem- 
brane. 
But even other situations have been indicated in which 
these growths may be met with ; thus Dr. Todd wrote : — ■ 
Bodies somewhat similar are also found occasionally on the 
choroid plexuses of the lateral ventricles. Very frequently 
we meet with granulations of a like kind in the fringe-like 
processes of pia mater which descend from the velum inter- 
positum to surround the pineal gland, and also upon the little 
processes of that membrane which go under the name of 
choroid plexuses of the fourth ventricle. Kolliker also states || 
that they are found in connection with the choroid plexuses 
of the ventricles. I have myself always failed to detect them 
in these situations, and on several occasions having cut off 
little opaque bodies from these vascular fringes, looking to 
the naked eye somewhat like Pacchionian bodies, have in- 
variably found them to be, after inspection with the micro- 
* 'Anatom Descrlpt.,' t, iv, p. 537. 
t ' Clinique Medical' Translated by Dr. Spillaii, 1836, p. 43. 
% 'Cyclop, of Anat. and Physiol,' vol. iii, art;. Nervous System^ p, 645. 
\ 'U'ber das Weseu der Paccionislien Drusen.' Miiller's *Arcliiv/ 
1852, p. 101. 
II 'Manual of Human Micros. Anat./ 1860, p. 243. 
