PATHOLOGY 383 mode of infection. The lymphoid cells become affected, not cer tainly in the way of atrophy, but in the way of transformation. There is indeed nothing more wonderful in the whole range of biological phenomena than to observe the adaptation of the cells and tissues of a lymph -gland to assume the cancerous structure already established in the organ to which they are related, an adaptation always close in its mimicry, involving the co-operation of large groups of cells and fibres, and directed as if by a presiding intelligence. In many instances the infecting substance may even want the perfect cellular character ; it may be no more than the detritus or the juices of cells and tissues. The most obvious form of infection, although probably the rarest, is where the new growth extends continuously along the sides or in the interior of lymphatic vessels from the secreting structure to the lymph-gland ; but even this continuous extension has been shown to be, not a protrusion of the primary tumour by increase or subdivision of its elements, but a succession of infective transformations along the line of cells constituting the lymph-vessel or investing it. Under all circum stances the lymph-gland becomes changed ultimately into a texture which reproduces with astonishing fidelity the particular pattern of the primary cancer, a pattern which is never quite the same in any two cases of tumour-disease even of the same organ. In some cases it is not always uniform throughout the same tumour ; thus pre parations might be described from a cluster of infected lymph-glands under the cancerous mamma of the bitch wherein two kinds of structure in the extensive strip of primary disease are severally reproduced in different lymph-glands. ection The infection of the liver is a very common sequel of cancer of liver, the digestive tract, as well as of other cancers, and even of sarcomas (especially the melanotic) and lymphomas. Opinions differ as to the share which the liver-cells take in the building up of the new texture ; but there is hardly any room for doubting that it is from the pre-existing cells of each infected area, even if it be exclu sively from the cells of the supporting tissue and the capillary walls, that the elements of the secondary tumours are derived by infective transformation. The infection breaks out and proceeds pari passu at a number of areas throughout the liver-substance, affecting the whole of an area as if at one blow ; there is an absolute lack of evidence in favour of the .assertion often made, that the secondary tumours are due to the mere increase, by division, of cells detached from the primary mass and lodged here and there in the liver. There is a certain amount of evidence in favour of some such embolic theory for the secondary tumours of the lungs, which are usually a sequel of sarcomatous growth in some bone or in other mesoblastic tissue. Sarcomatous tumours are apt to grow through the walls of neighbouring veins, and pieces of them doubtless get detached and carried into the pulmonary circulation ; but it is more than doubtful whether even these emboli give rise to the secondary tumours of the lungs merely by continuous proliferation of their cells, and not rather by the infective action of their presence. mary Another seat of secondary I sec- tumour-formation, both epi- lary thelial and melanotic sarco- sc- matous, is the serous mem- n. branes. The accompanying figure (fig. 54), from a nodule on the diaphragm in a case of cancer of the colon in the horse, may be set beside fig. 51 as showing the substan tial identity of the infective process in the secondary and primary seats of disease ; in both cases the cells of the connective tissue are seen in the stages of transformation towards the epithelial form and grouping. The infection Fro. 54. Cancerous nodule on the peritoneal of the neighbourhood is the Sl "^ acc , f diaphragm, secondary to cancer
- ?. , , of the colon (horse),
essence of the cancerous process. But the discontinuous infection of distant parts is not different from it in kind. It is merely "Wirkung in der Feme," and it is more mysterious only because it is more remote. The disorder of secretion thus eventually assumes a cancerous character in which traces of its origin may be hard to find. As the disease persists or extends the patient s colour becomes sallow or dull grey, the colourless cells are increased in the blood, the bones may become fragile, and general wasting (curiously associated some times with local production of fat at the seat of disease) puts an end to a life of suffering. In abdominal cancers death may be hastened by dropsy of the peritoneum ; in various forms of the disease there may be fatal bleeding from an eroded vessel. It has often been remarked that an appearance of exceptionally blooming health goes with the liability to cancer ; and the blooming appearance of the face and plump condition of the tissues will sometimes persist when the local ravages of the disease have made consider able progress. 1 9. THE LIABILITIES OF OBSOLESCENCE. We have seen in the foregoing sections that various liabilities to error underlie the embryological tissue -de velopments, the process of blood-making, the process of bone -making, and the process of secretion. But there are functions of the body, of its tissues and organs, in which the morbid liability is something special. The most striking instance of this is in the reproductive organs, particularly those of the female ; the obsolescence of the function, and in part of the structure, in the ovaries, uterus, and breasts of women long before the natural term of life creates a peculiar liability to disease. There are two other organs, the thyroid and the suprarenal, which hold a some what special position ; it cannot be doubted that each of these organs plays an important part in the economy, but there are suggestions in their morphology of survivalship from a former state of things, and their diseased conditions are not only peculiar in their occasion but also peculiarly important in their consequences. Lastly, there are two minute bodies situated at the bifurcation of great arterial trunks, the coccygeal gland and the intercarotid body, which are clearly marked as survivals; and the former, at least, of these carries a peculiar liability to tumour-disease during the period of intra- uterine life. These instances do not include the so-called "involution-diseases" or the liabilities of old age. The self -limitation of life may be said to be too large a problem for the present purpose ; but sexual involution is a part of this problem which comes directly into pathology. Cancer of the Breast in connexion v;ith Obsolescence of Structure Obsoles- and Function. The diseases of the climacteric period in women cence of make an important chapter in the special pathology of the sex ; mam- together with the disorders incidental to maturation, they stand mary for the larger part of the special ill health of women. It will not function, be possible in this article to give more than a single illustration of the morbid effects of this peculiar periodicity, namely, the obsolescence of the mammary function. The statistics collected by Paget clearly show that cancer of the breast in women is peculiarly a disease of the climacteric and post-climacteric period ; throughout the whole period from the age of about fifteen to about forty-five, during which the breast is capable of lactation, the cancerous disorder is rare in it, the tumour-disorders to which the organ is then liable being comparatively tractable. A few words about the physiology will serve to indicate the pathology of the simpler as well as of the more formidable malady. The reproductive functions in the female are not only peculiar among other functions of the organism in their maturation and obsolescence, but they are further remarkable for their periodicity within the period of vigour itself. In the lower species of the vegetable and animal kingdoms seasonal periodicity is in every thing, in the higher it is only in the sexual and secondary sexual characters, and in the human species it is practically confined to the reproductive system. The consequences, as regards the breast, are that its structure and function unfold during the term of gestation, continue in full vigour for a longer or shorter period (which may be arbitrarily limited), and then go through definite stages of subsidence and npfolding to the resting state. This periodical reduction of structure in an orderly way is a peculiar and unique thing; it is "as though a rose should shut and be a bud again." The upfolding and unfolding of structure have corresponding functional aspects ; there are crude secretory pro ducts formed and discharged, and hence it is that the breast is a peculiarly suitable organ in which to investigate the question of cellular by-products or waste of secretion, and their disposal by the lymphatic system. Compared with other secreting organs and parts the breast is not peculiarly liable to catarrh, but it has a physiological liability of its own which puts it on the same footing, as regards tumour-disease, with the great seats of catarrhal dis order, the stomach and the cervix uteri. Like these organs, it is not generally subject to cancer until after middle life ; but, where as in them the predisposition appears to depend on long-continued functional irregularities, the liability of the breast arises out of its 1 See Paget, Lectures on Surgical Pathology ; Riudfleisch, Die Bos- artigkeit der Carcinome, dargestettt als eine Folge ihrer ortliclien DC- structivitat, Leipsic, 1877 ; various contributors in Pathol. Trans., xxv., 1874; C. H. Moore, The Antecedents of Cancer, Loud., 1865 : K. Thierscri, Der Epithelialkrels, namcntlich der Haut, Leipsic, 1865.
