PART Il 
PATHOLOGY AND BACTERIOLOGY 
NOTES OF THE EXAMINATION OF AN EXOSTOSIS 
REMOVED BY MR. SYME ON OCTOBER 2, 1853, 
FROM THE OS HUMERI OF A YOUNG LADY 
AGED ABOUT TWENTY YEARS 
Read to the Edinburgh Medico-Chirurgical Society, November 16, 1853. 
[Monthly Journal of Medical Science, January 1854.] 
THE tumour was situated at the posterior and inner aspect of the bone, 
two or three inches from its upper end. Some idea of its general appearance 
may be gathered from Fig. 1 of the accompanying woodcut (see next page), 
which gives a lateral view of it of the natural size. It is seen to be of irregular 
form, presenting at its most prominent part several smooth rounded tuber- 
osities : these were covered with cartilage, while the more circumferential parts 
of the tumour rose gradually from the normal level of the bone around, and 
were destitute of cartilage. The whole surface of the tumour was invested 
with extremely loose cellular tissue, which must have allowed very free gliding 
motion of superjacent parts; this cellular tissue adhered firmly, both to the 
cartilaginous and osseous portions of the surface. At a, a piece of the tumour 
had been broken off, exposing the cancellated texture of the interior, which in 
the deepest parts of the exostosis, was extremely loose, consisting of medullary 
substance traversed by very delicate spicula, which presented the microscopical 
characters of true bone (a lacuna with canaliculi from one of these spicula was 
shown in a sketch at the reading of the paper). In the circumferential parts 
of the tumour, which, as above stated, were destitute of cartilage, this loose 
cancellous structure extended to within a very short distance of the surface, 
which was formed by a thin layer of compact, true osseous tissue. But beneath 
the cartilaginous prominences there was a considerable thickness of compact 
