had been perfectly well for the four following years. Then, on a recurrence of the tumour, a second excision was performed, after which the wound healed slowly, and the resulting scar was hard. The date at which I first saw this patient was four months after the second operation, and at that time there could be no question of the cancerous nature of the existing disease, although that first removed, as in the previous case, might have been held to be innocent.

Of these principal characters, which exhibit the alliance of Rodent with other Cancers, one has been very clearly stated by Mr. Cæsar Hawkins, when writing of warty tumours in cicatrices in the nineteenth volume of the Medico-Chirurgical Transactions.' After having distinguished Lupus and the corroding ulcer of the uterus,' as diseases which do 'not contaminate either the surrounding parts or the absorbent glands, by the formation in them of a new structure, like that developed in the seat of the primary disease,' and which also do not establish ‘a similar disease in another part of the body by means of this contamination,' he proceeds: But it seems to me, that we want some word for those diseases which do form a new structure, capable, apparently, of contaminating the surrounding parts, so that the removal of the whole of the altered structure is necessary, but which do not, as far as I know, produce

any contaminating influence upon the absorbent glands, and have no tendency whatever to reappear in a distant and unconnected part of the body. Such a disease is familiar to most Surgeons in the skin of the face of elderly persons, and is often, but I think erroneously, called cancerous and malignant, since, if the new structure at its basis be completely taken away, there need be no apprehension of any return of the disease, either in the same part or elsewhere; or at least, if the new structure really possesses the nature of Cancer, it must be clearly understood that the disease is cancerous and malignant in the very lowest degree.'

It is thus not only by the power of forming new structure, that the alliance of Rodent and other Cancers is manifested, but also by those additional resemblances in its subsequent progress, which have been detailed. The disease appears indeed, in accordance with the alternative which Mr. Cæsar Hawkins allows, to be a Cancer in the very lowest degree; and it is just such a form of that disease as we should expect to exist, if Cancer be primarily a local malady. For, whilst there are Cancers of high vitality and rapid growth, and capable of very wide diffusion in the body, there should be others, which being concentrated in their texture, or devoid of the means of disseminating themselves, are traceable only in the neighbourhood of their first outbreak. The

local characters of such diseases being alike, those dependent on the power of dissemination should be superadded in some of them. Just such, in general terms, is the difference between the Rodent and other Cancers. The Rodent Cancer is an exquisite instance of a local ailment, being almost uninterruptedly continuous in its growth, from the solitary pimple in which it originates, over an area of half the face. At the same time, however, that it has every local quality of Cancer, it is so meagre a growth, that it has no superfluous material for circulation in the blood to distant parts, and very little for the lymphatics and the textures nearest to it.

The natural history of moles and molluscous tumours needs further enquiry. Why should one on the scrotum produce melanosis, one on the face originate Rodent, of which diseases the former becomes universal, the latter remains local; one invades, and the other fails to contaminate the glands? Given the power of a single cell to produce a mushroom in a night; and one need not be surprised at the vigour of any morbid growth in a well-nourished body. But the extent which the growth will reach in one or other situations, since it is not determined by any manifest difference in the two moles, may depend on the natural vigour or feebleness of the textures adjoining it, in the contest of which for nutrition with the structures of the mole, Cancer arises. In

some degree Cancer does depend on vitality of site for its origin, so that it rarely occurs on the skin of the back, but arises commonly in that of the face.

THE TREATMENT OF RODENT CANCER.

THE distinction of the Rodent, and other ulcers, is in no respect more plain than in the effect of treatment upon them. These, in some period or condition, are curable by remedies applied to their surface, or by the correction of their constitutional cause; but the Rodent disease is neither healed by superficial applications, nor ever in any material degree improved by constitutional alteratives. Once only after an operation, in which a great Rodent disease was removed, and in which there appeared to be a renewal of the growth, I found the continuous use of small doses of the iodide of potassium improve the general health and reduce the marginal thickening. essential part of the disease is, in fact, not the ulcer, but the solid substance beneath it; and that treatment only is efficacious by which its deepest limits are exterminated.

The

This fact has long been familiar to Surgeons, and it has been customary, upon the failure of anti-syphilitic remedies, or those which cure scrofula, or which

simply invigorate the health, to spread a caustic upon the sore, and to assure the patient that, with the few hours' pain thus produced, his disease and suffering will be at an end. Those who recognise the nature of the disease lose no time in the use of ineffectual general treatment, but at once destroy the growth. The caustic burns through the entire depth of the solid disease, and, upon the casting of the subsequent slough, cicatrisation is rapidly completed.

For the production of this effect any of the ordinary caustics is adapted, provided only they be such as penetrate the tissues, and be used in a quantity adequate to the particular case. On a small sore the powder of arsenic is sometimes applied, either as Justamond employed it, or in the form of Plunket's paste, or in the combination with calomel with which the name of Dupuytren is associated. But it is always well to avoid the possibility of the absorption of arsenic, and to use rather the chloride of zinc, or the potassa fusa, or the Vienna paste, or the nitrate of silver, or the acid nitrate of mercury. There is no ulterior advantage in the employment of one rather than another of these caustics, and each Surgeon will select that with the action of which he is most familiar. I have been, myself, most satisfied with the chloride of zinc, and have the opinion that the temporary wasting of the natural textures adjoining those which its action destroys, tends to exhaust the