BastiaNj on the so-called Pacchionian Bodies. 97 
to them in tlie original progenitors of the race. Or are we to 
suppose that the conditions instrumental in bringing about 
their increase of size in after life have already been in opera- 
tion^ during the intra-uterine period, to a sufficient extent to 
produce the early rudiments of these structures,, ascertained 
by Luschka to exist in the new-born infant ? At all events, 
it does not appear that these bodies can be looked upon as 
isolated structures of an exceptional nature, in the face of 
what we know as to the existence of similar hypertrophic ex- 
crescences from other serous as well as synovial membranes. 
According to Wedl,"^ ^'^ papillary new formations/^ with a 
covering of epithelium, have been found by Heschl on the 
pleura, and especially on that portion over the lower border 
of the inferior lobes of both lungs ; whilst it is a well-known 
fact that in many cases the ^' white patches^^ of the visceral 
pericardium have a shaggy appearance when floated in water, 
from the presence of minute outgrowths, which would, in all 
probability, present, on microscopic examination, a fibrous 
structure, similar to that known to be presented by the opaque 
patch itself. On the other hand, the bodies developed from 
the synovial membranes of the larger joints, in cases of 
chronic inflammation, so well known to pathologists — often 
stalked and compound in form, but occasionally simple, 
smooth, ovate, compressed, and compared to melon seeds by 
Mayo — also present a fibrous structure, and may fairly be 
considered as having a close pathological relationship to the 
Pacchionian bodies.f Two causes seem influential in bringing 
about a fibroid thickening and opacity of serous membranes : 
undue amount of friction, on the one hand, which, as Dr. 
Jenner and other pathologists maintain, seems to be by far 
the most frequent cause of the ' white patches' of the peri- 
cardium ; and hypersemia on the other, whether from chronic 
infiammation or oft-repeated congestions, to which this con- 
dition of the arachnoid and synovial membranes seems most 
attributable. Repeated congestions alone are looked upon 
by Rokitansky and others as capable of producing opacity 
and thickening of the arachnoid, independently of any inflam- 
matory process. Some amount of it is generally met with 
after the middle periods of life ; and the same may be said as 
to the increase in number and size of the Pacchionian bodies ; 
* Loc. cit., p. 357. 
f la a more recent work ('Die Halbgelenke/ 1858, p. 46) than his com- 
munication before referred to, Luschka has shown that the central part of 
each intervertebral disc is a synovial sac, the membrane of which is developed 
into processes almost precisely resembling the Pacchionian bodies. {Note 
added June 19M.) 
