534 
ON HOCK LAMENESS. 
dently of this joint, and without any apparent change of struc- 
ture or external visible sign, except heat. 
Mr. G. received the thanks of many of the Society, and he 
had mine, though in silence, because I could subscribe to the 
truth of his observations relative to the seat and nature of ob- 
scure hock-lameness, although I could afford to differ with him 
as to the manner by which these lesions are developed. 
Professor Dick, in his reply to Mr. Spooner, thinks Mr. S. has 
fallen into error, and taken certain depressions in the articular 
surfaces for disease, which the Professor states to be no disease 
at all. For my own part, I do not doubt Mr. Spooner’s ability to 
distinguish what is inflammation ulceration, or mortification, 
either in membrane, cartilage, or bone. That denusion and a 
morbid process of absorption (the latter of which is taken for 
ulceration, at least generally so called) do take place of the 
cartilage and its membrane in various parts of the articular sur- 
faces of the joint between the tibia and astragalus occasionally, 
I can bear ample testimony ; and I can most positively assure 
Professor D., that neither I nor Mr. S. are in error with respect 
to those sulci, or pits, being lesions of the cartilage, but that 
he himself errs in respect to them. However frequent they are 
seen, they are true morbid lesions . What am I to say of those 
hock-joints, or of others, that are perfectly free from these de- 
pressions ? — That they are vices of structure? that they are de- 
ficient of excavations as retreats for synovia? No. Unless it is 
proved to me that an uneven surface is better adapted to receive 
weight, and endure wear and tear, than a perfectly smooth one, 
either in the mechanism of joints or door-hinges, there can be no 
necessity for such trifling reservoirs for the supply or husbanding 
of synovia. The secretion of it must be constant, and these ca- 
vities brimful, to anoint the parts as they pass, and thus to be of 
use, and this incessant pouring in of synovia renders them, in that 
view, absolutely unnecessary. Joints with true and beautifully 
smooth cartilaginous surfaces are sufficient evidence, without any 
other proof, of these said sulci being abnormal conditions of them. 
It is only in regard of the nature of these depressions that I 
differ with Professor D. I agree with him, that ulceration of car- 
tilage, the sequela of inflammation, is very rare — softening and 
morbid absorption being the more frequent consequence : carti- 
lage must be converted into bone previous to ulceration with pus. 
I agree also that these pits in the cartilage do not produce 
lameness, being out of the way of motion ; and for this further 
reason, that they are endowed with little sensibility, they are 
concomitants of bursal disease of the joint. In bog-spavin, I 
have observed one part of this said articulation denuded of its 
