STJRING-HALT-ITS DOUBTFUL PATHOLOGY. 595 
tlie affirmative; but sucli are not the open ulcers^ with gra¬ 
nular edges^ referred to by the doctor. This disease of bone 
has more the character of dry caries^ which gradually under¬ 
mines the cartilage of incrustation until a number of small 
pin-holes exists on the surface. Such a condition is often 
met with on the under surface of the navicular bone of the 
fore foot. In the hock it is likewise frequently met with 
upon the upper articular surface of the large metatarsal, and 
both surfaces of the cuneiform bones, and also on the under 
articular surface of the astragalus. I believe that this form 
6^ disease sometimes suddenly assumes a difPerent character 
when the undermined articular parts of the bone, and its 
much-thinned cartilage, caves in, if I may be allowed the 
expression. The exposed surface, and some little distance 
around it, becomes intensely inflamed; an unhealthy sanious 
discharge takes place from the surface of the sore, which, 
Avith the debris of the disintegrated bone, discolours the 
synovia, and is very likely to render it fetid. But this is 
not the so-called ulcer of Dr. Busteed. 
One word more respecting articular cartilage, for it is this 
variet}^ which the doctor refers to Avhen alluding to its ex¬ 
treme sensibility when inflamed. Now, structural anatomists 
know very well that this cartilage has neither nerves nor 
blood-vessels in it. How, then, can it become inflamed? 
How can it become so sensitive that the mildest dressing 
cannot be applied Avithout severe sufiering^^ ? I can fancy 
that the doctor will say, This is only quibbling. Of course 
I only mean the part from which the cartilage has been 
removed by disease, or the highly inflamed bone under the 
cartilage, Avhere it may not have been removed.^^ If this is 
Avhat the doctor means, I must apologise to him for alluding 
to it in the way I have done. I must think, hoAvever, that, 
so far as our knowledge goes, precision in our description is 
far less likely to lead to Avrong inferences. 
I can fancy that some of the readers of the Veterinarian 
Avill also say, You have endeavoured to pull down a theory 
that gives a definite cause for string-halt, which no veterinary 
pathologist has hitherto attempted, and in its stead you have 
merely stated your opinion to be that anything which Avould 
persistently, when the limb is in motion, irritate a certain 
nerve, is calculated to cause the afifection.^^ I admit that I 
have been by no means definite as to the cause of this malady. 
There is a mystery about it Avhich, for the present, is dark¬ 
ened over with a heavy mist that requires considerable re¬ 
search to clear away; and the remarks I have made upon 
Dr. Busteed^s paper, headed Doubtful Pathology,have 
