TRANSACTIONS OF THE SECTIONS. 165 
the sulphuric acid is to produce a new or false membrane, which is no 
removed by nature, as some other false membranes are, in consequence 
of its forming part of a solid body ; they serve also to confirm the opi- 
nion stated by the author in a communication read at the Bristol meet- 
ing—that false membranes, as in croup, balanites, bronchitis, &c., are 
the consequences of the presence of an acid preternaturally secreted in 
the fluids of the mucous membranes where these deposits occur, 
the organization of the albumen taking place under the coagulating 
influence of the acid. The treatment of opacity of the cornea produced 
by the action of sulphuric acid, appears to be elucidated in no small 
degree by these facts; if the acid be neutralized in the course of a 
few seconds, little or no injury is sustained by the cornea; but as in 
thirty seconds considerable opacity has occurred, and some portion of 
false membrane has been formed, it will be necessary to have recourse 
to the knife, which may be safely employed to scrape off the preterna- 
tural deposit. The author observed, that he intended to propose the 
operation to the patient described, so soon as the granulating action 
now affecting the eyelids had been subdued. 
Notice of an Ossified Tendo Achillis, and of a Case of Exostosis. 
By Dr. H. Lonspate, of Edinburgh. 
The author considered the former preparation unique, not being 
aware of any similar preparation in the museums of this country. 
The latter preparation illustrated osseous deposits in the tendon and 
muscular fibres of the crureus muscle, and an extension of this ossifica- 
tion to the femur itself, resembling an exostosis, but differing from the 
common exostosis in growing Zo, and not from the bone. The author 
designated it by the term Exostosis from without. 
The object which the author had (as stated in a brief communication) 
in exhibiting this latter preparation to the Section, was to counteract 
those exclusive opinions which many entertain on the subject of ossifi- 
cation ; and he considered that it was of value in showing that bone may 
be formed by vessels belonging to the soft parts, even in muscular 
fibres adjacent to one of the long bones, and more especially in point- 
ing out the caution which physiologists ought to observe in placing a 
limit to nature’s power. 
On Dislocation of the Anklejoint forward and backward ; and on the 
Reproduction of Bone after the Operation of Trepan. By JAMES 
Douctas, Lecturer on Anatomy, Glasgow. 
There is no satisfactory example on record of dislocation of the ankle- 
_ joint without fracture of one or both malleoli. There is no case on 
record of complete dislocation of the tibia forward, so that the inferior 
articular surface of that bone shall be completely in front of the articu- 
lar surface of the astragalus. A case has occurred to the author of this 
