around the scar may likewise become diseased anew, and that event, as in what is called true Cancer, may be delayed until some time after the supposed cure. Usually, no doubt, recurrence takes place in or near the scar, the Rodent disease resembling Cancer in this also, that it shows most intensity at its original site. But rare instances present themselves in which a separate growth does form in a part somewhat removed from that site; in which case apparently healthy structure intervenes between the primary and the detached disease. Whether the whole intervening structure were really healthy, it is not possible to say, or whether the renewed growth have a continuity with the old by some single diseased tissue. The occurrence, however, resembles that with which we are familiar in Cancer, in which an inappreciable yet real halo of disease surrounds the abrupt limits of the tumour. Thus this distinction between the Rodent and other Cancers is reduced to but one of degree, and intelligible from the mechanical conditions of the two growths. The limits of Rodent can be overpassed in an operation: those of scirrhus may not be.

The usual exemption of the lymphatic glands from enlargement is regarded as constituting a fundamental distinction between the Rodent and malignant diseases. But the conclusion appears to be as erroneous as that obtained by overlooking the import of the solid deposit in the natural textures

which precedes the Rodent ulceration. Enlargement of the glands is so usual in Cancer as to be one of its most useful and decisive characteristics, but it is not an invariable occurrence; and to look upon the power of infecting glands as essential to Cancer would be to confound Cancer with enchondroma or tubercle, which do the same, or even with a bit of tattooed gunpowder. It would also force an artificial separation between tumours identical in nature, especially scirrhus of the mamma, some of which fail altogether to travel beyond their original site, or, without infecting the glands at all, invade the liver. The cause and nature of the usual contamination of glands with Cancer are, indeed, not wholly understood, and the occasional healthiness of those subordinate organs still less so; but it is clear, without further knowledge on this subject, that a separation of the Rodent from other Cancers cannot be founded on that distinction. In its progress as a local tumour Cancer infiltrates indiscriminately all the natural textures, and this power equally characterises the Rodent disease. That it does not possess the additional and accidental property of dispersion with the lymph or the blood, or of growing if so dispersed, is not a reason for detaching it from the Cancers, which it resembles equally with a scirrhus that continues as a solitary tumour until death.

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Apart from any structural peculiarity of the disease, there appear to be obvious mechanical reasons for the usual failure of the Rodent Cancer to be repeated in the adjacent lymphatic glands. On the one hand, the stream of natural lymph to the glands must be progressively diminished, as the textural area from which the lymph should come is scooped away; and that stream, on the other hand, can be but little replenished with the scanty material which is derivable from a growth so slow, and at the same time so perishable, as the solid margin of a Rodent Cancer. Moreover, not only are the natural textures reduced in quantity, but those which still exist are usually attenuated. The demarcation of normal and abnormal structure feels the more abrupt because of the emaciation immediately adjoining the disease, there being, except in particular situations, not even oedematous swelling. There is, consequently, little material which might pass from those textures to the glands. Again, since the principal increase of every cancerous tumour is on the exterior, and is mainly due to the tense compression of its oldest central substance and contained bloodvessels, and the consequent forced filtration of its growing materials into the looser textures surrounding it, then in the Rodent Cancer that condition also is in great part wanting. The filtration must set the other way, inasmuch as so

little substance intervenes between the growing and the ulcerating surfaces of the solid marginal deposit. Superfluous matters tend to escape on the freer open surface, and thus avoid the glands.

But it may be that there are causes in the nature of the disease itself which explain its failure to infect the glands. The matters which it yields to them are not viable. In the growth itself there are not usually masses of exuberant and rapidly growing cells, but such as at best have but a feeble and precarious life; all the less, therefore, can those fragments of it which may be dislodged retain any power of further development in the new and less propitious circumstances into which they may be transplanted. They have never any of that activity of growth which is characteristic of ordinary Cancer in glands, but are only those scanty, liquid, and effete parts of the primary disease, which, as they enter the lymphatics and traverse the glands, are eliminated without harm and without being noticed in their transition.

Were there, however, always, as there appears sometimes to be, in the Rodent disease a material as ready to produce secondary deposits as is met with in ordinary scirrhus, its failure to infect the glands would still be not without parallel in certain cases of that disease. For glandular infection, as has been already stated, is not an invariable accompaniment of

true Cancer. In scirrhus it is the rule, not without exceptions, for the glands to be secondarily diseased; in Rodent, the rule, equally liable to exceptions, is for the glands to be unaffected. To explain this, if even it can be explained, would require a long investigation into the relation of the glands to Cancer. I may, however, briefly state some conclusions, to which the observation of different cases has led me, respecting the manner in which glands sometimes escape infection from a primary Cancer.

It being allowed that such infection is mechanical, then those organs fail to share the primary disease either

1. Because by the compactness and excessive slowness of its growth the Cancer furnishes nothing for distribution.

2. Because materials which are distributed are inert. 3. Because, when itself withering, the primary tumour yields nothing which could grow elsewhere.

4. Because, though growing, its elements find no convenient outlet towards the glands.

5. Because the lymphatics are shrunken. Or,

6. Because the stream in them is sluggish, or is diverted.

In either case, some requisite condition for the infection of the glands is wanting. If the absence of it suffice to explain the occasional exemption of the

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