CLINICAL LECTURES.

CANCER.

BY ERNEST LAPLACE, M.D., LL.D.,

Professor of Surgery, Pathology, and Clinical Surgery in the Medico-Chirurgical College of Philadelphia; Visiting Surgeon to Philadelphia Hospital, etc.

I

WISH, to-day, to give you a few general thoughts on cancer,—an affection of such dread to all who are acquainted with it; so difficult to diagnosticate and treat,—cancer, the bugbear of the medical student, especially when called on to distinguish between it, sarcoma, and other growths. To begin with what we know about cancer. The word cancer means simply a crab, so named by the ancient pathologists from its eating or gnawing. At the present time it means nothing else than an hyperplasia, or excessive development, of the cells in a particular part of the body. Now, these cells may either grow on the surface and bulge out or they may grow on the surface and dip into the tissues. According as they do one or the other, they are benign or malignant growths. Let us say, by way of illustration, it began on the surface of the skin in the epithelium. You all have been out rowing, and have noticed how callous your hand would become and how here and there was a "water blister." The oar acts as an irritant to the skin, and a congestion and hypernutrition is the result; the epithelial cells proliferate, accumulate in the one spot, and there is a tumor or callus, under which may be found blood-serum, which, being absorbed, leaves the thickened epidermis.

On the other hand, the man is a smoker and smokes a pipe. The pipe always rubs the

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same spot. That man comes from a family of cancerous ancestors, and has a suitable soil or predisposition to cancer, if the chances are given for an irritant to enter the tissues. The man may have an abrasion on the lip; the pipe irritates it and causes an hyperæmia. Furthermore, there is another element that comes in, and this is a micro-organism. I cannot prove to you that this is the case, nor can I show you the germ, but it is allied to the germs that we know are the cause of other affections. In the case of the thickened epidermis of the hand, and when we have a corn on the foot, we have an irritant acting from without; but in epithelioma the irritant-a germ-acts in the tissues and causes the growing epithelium to be pushed down, and causes it to infiltrate into the tissues, while in the corn it is simply an accumulation of the epithelial cells on the surface. The ordinary corn or callus is an epithelioma in the true sense of the word, but time and usage have determined us not to call this an epithelioma. Now let us return to our smoker.

The pipe has irritated the crack or abrasion of the lip. The man is of a carcinomatous diathesis; just what a diathesis is we do not know, but he has the chemical condition within him which makes him a suitable soil to develop cancer. Such a condition is tuberculosis, that springs up from grief or exposure. Many thousand people smoke a pipe and do not get cancer, because they do not have the diathesis. As a result of the irritant, the cells proliferate and produce a chemical substance called a toxin. This increases the irritation on the inside and causes the proliferation to continue. The cells do not accumulate on the surface, but infiltrate into the subcutaneous

The processes of nature are blind, and she acts just as she is forced to act. When we have an amputation, the large flaps are open, and a dreadful gap has been made. The surgeon cleanses the wound, renders it aseptic, sews it up, and trusts to nature to cure it. All the elements that are concerned in cancer are brought to bear here, and grow and heal the wound. The very element that nature puts in the most malignant cancer enters into the process of healing wounds. In a cut or wound, as a result, a clot forms in the mouth of the vessels and checks hæmorrhage. The blood is still being forced into the vessels, and in these vessels are small mouths or stomata against which a white blood cell fits. The cells enter into the stomata and, by an hourglass contraction, escape from the vessels as leucocytes, giving us the phenomenon of diapedesis. The leucocytes are destined by nature to grow into fibrous tissue by their elongation. When millions of these leucocytes are exuded into the wound, we say it is covered with healthy granulations. These soon fill the wound, and it is found that those which fill the bottom of the wound have become fibrous; above this come the spindle-shaped and on top the round cells. Finally, all that remains to complete the healing is to cover it with epithelium. If, for some reason, the leuco cyte had not grown, but had been killed, it would have undergone fatty degeneration and given us a pus cell. You must retain these steps and follow them closely if you wish to get an accurate notion of the development of cancer.

You will find nothing but fibrous and epi thelial tissues in cancer, but they are arranged differently from the normal tissues of the body. Sarcoma is a variety of fibroma. Just as epithelioma is a variety due to the growth of epi

fibrous cells. In fibroma there is an exudation of cells from a vessel which undergo the same changes that they do in the healing of an ordinary wound. If you make sections of a fibroma and examine them with a microscope, you will find cells of different ages, representing the round, spindle, and fibrous cell, all in the same tumor. When you find the fibrous cells in excess, it is a fibroma; when the spindle cells predominate, it is a spindle-cell sarcoma; and if the round cells are in excess, it is a round cell sarcoma. A fibroma and a sarcoma are really the same thing, but the sarcoma grows much more rapidly than the fibroma. A fibroma cannot become a fibroma until it has undergone the same process of growth as a sarcoma,—only very slowly.

The carcinoma develops either as the soft encephaloid or hard scirrhus in the glands. Just as we have the epithelioma on the surface, we may have a growth of endothelial cells in a gland, giving us the encephaloid (brainlike) cancer. When the mass is simply composed of endothelial cells with a very small amount of fibrous tissue and without structure, it is the encephaloid. A scirrhus is nothing else than a combination of the encephaloid and fibrous tissue in which the fibrous tissue predominates. It is much harder than the encephaloid, but the process of development is the same. The epithelial cells are inclosed within fibrous cells, forming alveoli.

We next come to consider the mucoid and amyloid cancers. Nature can do nothing more than I have stated, and these cells, growing under abnormal circumstances, die and, being contracted upon by the fibrous tissue, undergo amyloid, mucoid, or calcareous degeneration, giving us these forms of cancer.

Metastasis. To my mind the very best proof of malignant growths being due to a micro-organism is the element of metastasis,— that element by which a growth, if not properly removed, will break out anew in the same or another place, as only one germ is required to develop it. A tumor may be thoroughly removed, but, if a neighboring gland be affected, what can be plainer than that the poison has traveled along the lymphatics and developed? Here is an idea I wish to submit to you that will take away any absolute or stereotyped rule, and that is, when to pronounce a growth benign and when malignant. Why