OBSERVATIONS ON STRINGH^VLT. 
663 
the dreadful pain causes the animal to keep it in continual 
motion^ but then only when not compelled to walk. In dis¬ 
ease of a joint, the freedom of movement is generally in pro¬ 
portion to the extent or severity of the disease; the more 
formidable this is, the less the articulation is exposed to irri¬ 
tation by movement, or supporting weight. 
In stringhalt the flexion is spasmodic, or highly exaggerated, 
offering; a range of motion the reverse to that we should see 
O O 
were the hock articulations diseased; indeed it is the verv 
^ •/ 
opposite of what we regard as lameness. 
Dr. Busteed must likewise have noticed that the free play 
of this ginglyrnoid joint in stringhalt is not limited to 
flexion only, but manifests itself also, to a certain degree, in 
sudden and forcible extension—not at all indicative of hock 
ulceration —when the foot of the affected limb comes to the 
ground with a highly magnified tread. 
With Professor Varnell, I am ready to conclude that Dr. 
Busteed’s irritable ulcer of the astragalus—so curiously dis¬ 
covered always in the same situation—is nothing more than 
the congenital or sulcus; but Dr. Busteed is 
not the first amateur in horse matters who has made this 
trifling mistake. What would particularly lead one to 
infer that the doctor has made this blunder* is to be found 
in the description of Case 7, where he says that the sinus 
of the inferior portion of the groove in the astragalus, 
which must not be mistaken for an ulcer, was very deep 
and but thinly covered hy cartilage. This evidently shows 
that the doctor is not quite an fait in the anatomy of these 
sulci, else he would know that they are not covered by car¬ 
tilage, and that this material terminates abruptly around their 
margins. Again, he says, in the same case, ‘'^the synovial 
tissue was deey and but slightly covered ivith cartilage.^’ What 
does this mean? Is the structure of the synovial tissue 
different in America to what it is in Europe ? and in this 
case, too, strange to relate, the irritable ulcer is found on 
the astragalus of a limb not affected by stringh.alt, though 
this does not seem to militate against the doctor^s theory.or 
opinion. 
The lesions of articular cartilage, in the domestic animals 
as in man, are known to be exceedingly obscure, their vitality 
feeble, and their vascularity and sensibility, as Professor 
Varnell observes next to, if not quite null. From their non¬ 
vascularity, articular cartilages are not liable to ulceration, 
though they may suffer from absorption or softening, as a 
sequel to disease, affecting primarily the other textures which 
enter into the composition of the joints, and notably that of 
