Though of small size, and not possessed of malignant action or disposition, is a tumour of very great interest, on account of the excruciating pain with which it is accompanied. It is mostly situated in the subcutaneous cellular tissue, but not unfrequently in the intermuscular cellular substance; one tumour of this species which I have removed was so deep as to be in immediate contact with the sheath of the posterior tibial nerve. The tumour, generally of the size of a garden pea, rarely exceeds that of a cherry. It is invested by a dense ligamentous cyst, to which it intimately adheres; but occasionally the capsule is thin and cellular: in many instances its surface is perfectly smooth, in others it is slightly nodulated. It is not connected with any large nervous trunk; but minute nervous fibrillæ can occasionally be traced expanding on its surface, and apparently entering its substance. Internally it is composed of numerous whitish fibres, of considerable density, ramifying irregularly throughout its structure; and betwixt these is insinuated a firm substance, generally of a grey colour, and frequently of an almost cartilaginous consistence. Such is the structure most frequently observed; but in this morbid formation, as in all others, the appearances may be said to vary in almost every instance. Sometimes the fibres are indistinct, and of a yellowish or dirty grey colour; and the interfibrous matter is often found to vary in density and colour in different tumours, being at one time dense and almost transparent, at another opaque and cartilaginous, and sometimes rather soft, brownish, and occasionally tinged with blood. From attentive examination, it appears extremely probable that the enlargement is at first produced by infiltration of lymph betwixt the fibrillæ of a nervous twig, which becomes separated and inclosed by the deposit—that they afterwards increase in size—that the interfibrous matter is deposited in greater quantity, and is farther condensed—and that thereby the nervous filaments are still more separated and extenuated. In short, it would appear that the fibrous matter is nervous, though altered, and that the interposed substance is organised and condensed lymph. The tumour, at first extremely minute, enlarges slowly; when deep, it can only be obscurely felt, and its existence is with difficulty discovered by manipulation; but the attending symptoms are so peculiar, and so forcibly developed, as to lead the surgeon at once to an accurate diagnosis. When it is subcutaneous, the skin is rendered slightly prominent, and the size, density, and loose connections of the growth, are readily ascertained. The slightest pressure causes the most excruciating torments, and totally unmans the patient, even though induced by the most trifling movement of the adjoining muscles. From a fearful and well-grounded knowledge of this circumstance, the patient is extremely anxious to