156 
HISTOLOGY OF ANIMALS. 
cartilages have been already noticed. In the adult con- 
dition, as shown in a portion of the head of a metacarpal 
bone, Fig. 1 20, a, the vessels are equally numerous, and 
when magnified at least twenty 
diameters, their looped ter- 
minations b are well dis- 
played ; they not only are 
continued upon the cartilage 
as far as the parts concerned 
in locomotion, hut in some 
cases processes of the mem- 
brane, like fringes or 
villi, richly supplied with 
vessels, project into every 
nook and corner where they 
are not liable to injury. These processes, which in 
the knee-joint were described by Clopton Havers, and 
stated by him to possess a glandular office, have upon 
more recent investigation been presumed to be entitled 
to such a character as Havers ascribed to them, although 
most anatomists since his time have regarded them as 
masses of fat. If one of the joints of a finger be laid 
open, the vessels of the synovial membrane forming the 
capsule of the joint will be found thrown into a series of 
processes like villi, which are largely supplied with 
vessels remarkable for their tortuosity. These villi pro- 
ject into all parts of the cavity of the joint, and the 
vessels are supposed to pour out the synovia ; they 
may, therefore, be viewed as synovial glands. The 
FIG. 120 . 
Vessels of synovial membrane : 
a, portion of the head of a meta- 
carpal bone of an adult with the 
synovial vessels injected ; b , ves- 
sels from a part of the same mag- 
nified 20 diameters. 
