By attending to these circumstances, we may generally form a pretty just diagnosis. At the same time, it must be admitted, that, occasionally, cases do occur, in which it is impossible to deliver a decided opinion: Nor is it doubtful, that many ulcers are considered as cancerous, which are of a different nature, and some of which admit of a cure. In forming our judgment, we must be directed by the nature of the first symptoms, and the history of the schirrous stage; by the appearance and aspect of the fungus, and the other circumstances which have been already described.
Concerning the peculiar state of the parts in cancer, or the proximate cause, many opinions have prevailed; but these, however they might differ in certain points, have almost unanimously agreed in admitting obstruction as the chief cause of this disease.
Until lately, the melancholic humour was supposed to be the fluid which was obstructed, and accumulated, in consequence of which it fermented, and produced a burning ulcer; and whatever promoted the generation of this humour, was currently admitted as a remote cause of cancer. Women, says Ambrose Paré, are more subject to schirrus than men; “because their liver is warmer, and their spleen being weaker, is less able to purge the blood of choler.” Grief and chagrin, by promoting the formation of this fiery fluid, were accordingly considered by the celebrated Heister, as very apt to induce the “cancerous diathesis;” and he slyly adds, by way of corollary, that “old maids, and women who do not breed, are very subject to cancer in the breast[115].”
Concerning the particular changes which took place in the nature of this obstructed humour, many different opinions prevailed. Some thought it necessary, that the black bile should be charged with an acid, and that this produced ulceration, when “its sharp cutting points had surmounted and destroyed the volatile smegmatic and balsamic salts of the blood.” Others conjectured, that by an “adustion or over-concoction,” it grew sharp and burning: But Wiseman observes, that it is more probable that it becomes somewhat arsenical. It would, however, be useless to enumerate the different changes which this imaginary humour was supposed to undergo. It is sufficient to observe, that these were almost universally believed to depend upon the previous stagnation, in consequence of obstruction; and this leading point has uniformly been insisted on by every succeeding author, whatever might have been his particular notion with regard to the nature of the obstructed fluid, whether bile, blood, or lymph; and even the anatomical structure of the part has been brought in support of the doctrine of obstruction. One of the latest writers[116], though he talks nothing of “coagulating acids[117],” yet insists fully on this mechanical cause as the origin of cancer; “for,” says he, “the circulation in the glands being carried on by a set of vessels much more minute than those with which other parts of the body are supplied, (let this be proved), obstruction will much more readily and easily occur in them than in other parts.”—“When the substance of a gland happens to be the part, a determination is made to this, being neither, as is found by experience, so proper as the cellular substance, or the formation of pus, nor, from its softness[118], so susceptible of inflammation, as a membrane; an indolent hard swelling, called a schirrus, comes, merely by the obstruction and distension[119] of its different vessels, very naturally to be produced.”
Some surgeons, perhaps from a desire of singularity, or from a defect of their organs of sight, declared, that they had detected little worms in the parts, which, eating it up, produced all the disagreeable symptoms of cancer; and that to their introduction the disease was owing. The cure which they confidently proposed, was applying a piece of cold veal to the part, which would tempt the animals to quit their devastation. Others, perhaps originally from ridicule, though latterly in sober earnest, told their readers, that there were no worms, but a little wolf in the part, which might be made occasionally to show its head, by holding a piece of meat before the ulcer.
Strange as this doctrine of living creatures producing cancer may appear, it is nevertheless adopted by a late very ingenious writer. When hydatids find their way into “a solid substance,” the consequence, in his opinion, will be cancer; and the success of an operation will, he conjectures, depend, in a great measure, upon these animals being confined in a common cyst, for then they may be all removed; whereas, if they be unconnected, some of the smaller ones may be allowed to remain[120]. From the surface of the cyst, which contains the animal, a fungus shoots out, and thus acts as a barrier between it and the skin; or, if the animal have been in the stomach, it separates it from the coats of that viscus, “preventing suppuration in the one instance, and absorption in the other[121].” This suppuration, “and disposition to fungate before the skin is broken,” if I understand him, is produced by the death of the animal; for, says he, “if hydatids possess the principle vitality during their transparent state, and their opacity is the effect of the loss of that principle, would they not, in the latter stage, stimulate the part in which they are situated to suppuration, as we find the case with the Guinea worm when dead[122]?” Concerning the manner in which these animals produce the symptoms of cancer, we are told, that “this enlargement of a foreign body, in a solid substance, and so extremely sensible as the breast, cannot but be attended with intense pain, and frequent inflammation[123].” A doctrine not far removed from that taught in the humoural schools, which maintained, that the coagulation and inspissation of the fluids distended the follicles of the glands, producing many cavities, and much pain[124].
That hydatids may be formed on a cancerous gland, I shall not dispute; but that they are generally to be met with, or are in any respect essential to the disease, I cannot admit. In all the cancerous breasts, testicles, and tumors, which I have examined, I never saw any thing which could be considered distinctly as a hydatid; so that I suspect, that under this name have been described the small cancerous abscesses, with thick cartilaginous sides, which we so universally meet with in schirro-cancerous glands. We likewise find cancer take place in circumstances in which no hydatids can be found. Thus, for instance, a cancerous wart being knocked off the face, a cancerous ulcer is produced; but no hydatid is to be found at the base of the wart to produce this.