NAVICULARTHR1TIS. 
545 
“ In the earlier stages of the disease there is deficiency of synovia, 
but not a total absence of it ; the secreting synovial membrane 
highly inflamed, &c. — In the advanced stage of the complaint 
there is a total destruction of the joint, which is so completely 
disorganized that it can no longer act as a joint. There is 
not a drop of synovia to he found in it.” This constitutes what is 
called the dry state of joint; and it seems like a remarkable 
occurrence in a bursal cavity — which the navicular joint in reality 
is ; it being so well known that inflammatory action in hursce is 
commonly productive of augmented secretion of synovia, as is 
instanced in the capped hock, the windgall, & c. For my own 
part, however, I do not regard this deficiency of synovia in the 
navicular joint as an anomaly to the general law of articular in- 
flammation. I very much doubt that in the earliest stages of navi- 
cularthritis the synovial secretion is diminished ; I should rather 
feel inclined to think it was augmented, although it may b( ex- 
tremely difficult to produce demonstrative proof either of one state 
or the other in that incipient stage of the disease which alone could 
turn out satisfactory. 
0 As, however, the disease in the joint advances, and ulceration 
comes to destroy, or interstitial deposition to change, the secretory 
structure of the synovial membrane, the secretion, of course, would 
become scanty, and even wanting altogether ; and this I suspect 
to be the history of the dry navicular joint; and not, as I said be- 
fore, anything different in the inflammatory action from what hap- 
pens, under like circumstances, in other joints and bursal cavities. 
Ulceration of the Cartilage speedily follows, if it be not 
simultaneous in its appearance with, the inflammatory action. It 
must be remembered that the synovial membrane clothing the ar- 
ticular cartilages is of that tenuous character, that its existence 
upon such parts was for a long time disputed ; and that no sooner 
is it attacked with inflammation, than from its low degree of vitality 
it, or rather the cartilage underneath it, falls into a state of ulcera- 
tion ; and it is the most prominent point of the cartilage, the part 
most remote from the source of circulation, which is the first to 
fall into this state ; and the same may be said of the hollowed 
central point of the cartilaginous capsule of the tendon opposite. 
Once commenced, ulceration spreads down the sides of the navi- 
cular crest, giving the formerly smooth and shining surfaces of the 
bone the patchy eroded aspect which has been well characterized 
as looking like worm-eaten ; at the same time that, owing to the ul- 
ceration, and to the attenuation as well, of other parts of the articu- 
lar cartilage, discolouration is very visible : the surfaces having, in 
exchange for their humid and shining aspect, taken on them a 
dead and dingy brownish tinge. 
