In attempting to describe, or even to arrange the remaining diseases of the osseous system, the pathologist has to encounter difficulties al most insurmountable. Some of these are na tural to and inseparable from the subject, as ist, the depth at which a bone may be situated will render it difficult to discover a change of shape or size, much more to ascertain an altera tion of structure. 2d. The bones do not al ways exhibit a very active sensibility ; when attacked by chronic forms of disease, they do not cause very great pain, and consequently the evil may be well established and irreme diable before the patient is fully sensible of his condition. 3d. These affections are not fatal at an early period ; they run a long and tedious course before they destroy life or render the removal of the limb indispensible. And hence in any individual case it may be difficult to learn even the early history or commencing symptoms, much more the nature of that pecu liarity of constitution that disposes to these diseases, or the first changes that take place from a healthy to a morbid stnicture. Little, indeed, can be ascertained with certainty as to the nat_re of osseous tumours until the part has been removed, and then the information comes too late for any useful purpose. Another source of embarrassment exists in a want of ac cordance as to the nomenclature of these affec tions. One surgeon calls that exostosis which another has named osteo-sarcoma, and a third has designated as cellular exostosis an affection which he himself in another place has named spina ventosa. In order, in the present in stance, to avoid similar confusion, we must endeavour to construct an arrangement which shall give to each class of disease its own ge neric term ; and although occasionally such deviations from the usual operations of nature will present themselves to the pathologist as to baffle all his attempts at classification, still we believe such a foundation as we allude to will be eminently useful, whatever superstructure may be raised upon it.
Spina our museums of morbid anatomy, there is no want of specimens exhi biting the separation, or rather expansion of the solid walls of a bone, leaving one or more cavities within it ; these cavities having during the patient's life been filled with a secretion that presents considerable variety in different cases, sometimes possessing a moderate degree of firmness and consistency, but more frequently consisting of a fluid of a serous character and reddish colour. This is the disease to which we apply the name of spina ventosa in contra distinction to abscess within a bone, from which it differs in its extremely chronic nature and tedious progress ; in its not containing purulent matter ; in its having no tendency to burst into any contiguous joint; and (until at a very ad vanced period) in its not being complicated with caries.* Boyer divides this disease into two species, one of which is peculiar to chil dren, and continues to the age of puberty ; the other, the spina ventosa of adults, which ex hibits the characteristic features of the disease more perfectly.
It is, indeed, difficult to separate the first mentioned of these affections from our com monly-received notions of caries, and in the various instances we have seen we have always regarded them as such. Boyer attributes it to the influence of a scrofulous taint within the system, and says that it attacks the metacar pus, the metatarsus, and the phalanges. It commences and continues for a length of time either without pain or with very trivial suffer ing ; the tumefaction of the parts is moderate, their motions scarcely interfered vvith, and re covery filially takes place about the age of pu berty by a species of necrosis. Its course is
thus described : " The progress of the disease and the distension the soft parts undergo, cause them to ulcerate at a spot always corresponding to some aperture in the osseous cylinder, and permitting the introduction of a probe within its cavity. The external aperture becomes fistulous, and for a /ong time discharges a moderate quantity of ill-digested serous matter. The part, however, remains indolent, the con stitution does not suffer, and if the patient can thus attain that epoch of life at which nature commonly can struggle with success against scrofula, this form of spina ventosa may be cured by necrosis of a part of the spoiled bone. Then the sequestrum is detached, the re mainder of the osseous parts subside, resolu tion is established, and the disease ends by a deep, adherent, and deformed cicatrix." We have not met with the affection as here described —we have never seen any thing like the rege neration of a bone thus lost, nor can we con ceive necrosis, which is essentially a reproduc tive process, to be in anywise allied to or con nected with scrofula; we therefore still regard this disease, which after all is not very frequent of occurrence in these countries, as a modifica tion of caries.
" The other species, fortunately more rare but much more serious, most frequently attacks adult persons, and affects the extremities of the long and cylindrical bones of the limbs." Its exciting cause seems to be involved in utter obscurity, nothing being known with certainty concerning it. Very often the patient traces it to the receipt of some injury, bnt it occurs so frequently without any such provocation, that it must be considered as an idiopathic disease. It is found most frequently, as Boyer has re marked, in the long bones, where the medullary cavity is best developed, but it is seen in the flat bones also, and in so many instances in the lower jaw as to render it an object of attention with reference to this bone alone. Its com mencement has no chamcteristic by which it can with certainty be known, and its progress is equally variable, being generally slow, but sometimes remarkably rapid. It commences with pain, occasionally deep and dull, occa sionally severe to excess, either when its pro gress is rapid, or it presses on some sensible or important part. This pain, with very few ex ceptions, precedes the swelling, and when the disease attacks the lower jaw is almost con stantly mistaken for common tooth-ache—a mistake that leads to the extraction of one or more of the teeth and the consequent exacerba tion of morbid action. The tumour seems to engage the entire circumference of the bone, if it be a round one; if flat, the swelling is more oval, and sometimes it is irregular and lobula ted. It is hard, firm, unyielding, and incom pressible : pressure on it does not occasion an aggravation of pain, unless it shall have hap pened that the periosteum is inflamed, when of course the smallest pressure will occasion suffering. In the commencement it bears a strong resemblance to necrosis of the long bone, except in not being preceded or accompanied by fever, and in not being so painful or so rapid in its progress. In the flat bone it has a greater likeness to osteo-sarcoma, from which it is so difficult to distinguish it that many cases of spina ventosa have been operated on and removed as examples of the other disease. Nevertheless at a more advanced period the diagnosis is more easy, for spina ventosa does not reach the great, or rather the illimitable size to which osteo-sarcoma may attain.