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TRANSFERENCE OF INFECTION. 459
conclusion in the matter, than that the degeneration of the neighbouring parts arises in precisely the same manner as that of the nearest lymphatic glands which lie in the course of the stream of lymph which proceeds from the diseased part. The more anastomoses the parts possess, the more readily do they become diseased, and vice versa. In cartilage malignant affections are so rare, that it is usually assumed to be altogether insusceptible of them. Thus in a joint the cartilaginous investment alone is sometimes found intact, whilst everything else has been destroyed. Thus too we see that fibrous parts which are rich in elastic elements, are very little disposed to become diseased by contagion. On the other hand, the softer a basis-substance is and the better the conveyance can take place, the more certainly we may expect, that, when occasion offers, new foci of disease will arise in the part. I have therefore come to the conclusion—the only one I think the facts warrant— that the infection is directly transferred by the means of morbid juices from the original seat of the disease to the anastomosing elements in the neighbourhood, without the intervention of vessels and nerves. The nerves are indeed often the best conductors for the propagation of contagious new-formations, only not as nerves, but as parts with soft interstitial tissue.
Here we have the importance of the anastomosing cellular elements of tissues, and the value of the cellular theory most clearly exhibited, and, when once we have become acquainted with this mode of conduction, we are afterwards able with a certain degree of probability to foresee in what direction, in parts possessing this means of conveyance, the disease will extend, and where finally the greater or less danger lies. It has hitherto been impossible to prove whether the infection of remote parts is effected by the conveyance of juices, in the same way that the infection of neighbouring parts is, and especially whether the blood takes up anything noxious from the diseased spot and conveys it to a distant place. I must confess that I am acquainted with no sufficiently convincing facts bearing upon the matter, and must still allow it to be possible that the diffusion by means of vessels may depend upon a dissemination of cells from the tumours themselves. There are, however, many facts, which speak but little in favour of the infection's taking place by means of really detached cells, for example, the circumstance that, certain processes advance in a direction contrary to that of the current of lymph, so that after a cancer of the breast, disease of the liver takes place whilst the lung remains unaffected. Here it seems pretty probable that juices are taken up, which occasion a further propagation (p. 219).
Allow me still to add a few words upon a subject which can here be dispatched off hand, namely the so-called parasitism of new-formations.
It is self-evident, that the view taken of parasitism by the old writers who held it to be applicable to a large proportion of new-formations, is completely borne out by facts, and that in reality every new-formation which contributes to the body no serviceable structures, must be regarded as a parasitical element in the body. Only bear in mind that the idea conveyed by parasitism does not differ from that conveyed by the autonomy of every part of the body excepting in degree, and that every single epithelial and muscular fibre-cell leads a sort of parasitical existence in relation to the rest of the body, just as much as every individual cell in a tree has in relation to the others a special existence, appertaining to itself alone, and deprives the remaining cells of certain matters. Parasitism in a narrower sense of the word, develops itself out of this idea of the independence of individual parts. As long as the requirements of the remaining parts demand the existence of a part, as long as this part is in any way PARASITISM. 461
useful to the other parts, so long will it not be termed a parasite; but it becomes so from the moment that it becomes foreign or injurious to the body. The epithet, parasitical, must therefore not be restricted to a single class of tumours, but applies to all heteroplastic forms, which do not in the course of their further metamorphoses give rise to homologous products, but furnish neoplasms which in a greater or less degree are alien to the composition of the body. Every one of their elements will withdraw matters from the body which might be used for other purposes, and as it has at the very outset destroyed normal parts and even its first development presupposes the destruction of its parent structures, it both plays a destructive part at the commencement of its career, and a depredatory one throughout its course.
APRIL 27, 1S5S.
FORM AND NATURE OF PATHOLOGICAL NEW-
Nomenclature and classification of pathological new-formations.—Consistence as a principle of division.—Comparison with individual parts of the body —Histological division.—Apparent heterology of tubercle, colloid, &c.
Difference of form and nature: Colloid, Epithelioma, Papillary lumour, Tubercle.
Papillary tumours: simple (condylomata, papillomata) and specific (villous cancer and cauliflower-tumour).
Tubercle: infiltration and granulation.—Inflammatory origin of tubercle.—lis origin from connective tissue.—Miliary granules, and solitary masses.— The cheesy metamorphosis.
Colloid: myxoma.—Collonema.—Mucous or gelatinous cancer.
Physiological types of heterologous new-formations: lymphoid nature of tubercle, ha?matoid of pus, epithelioid of cancer, cancroid, pearly and dermoid tumours, and connective-tissue-like of sarcoma.—Infectiousness according to the amount of juice.
Comparison between pathological new-formations in animals and vegetables.— Conclusion.
If, gentlemen, we prosecute the train of thought which we have pursued in the last lectures, it seems to me that the question which you will perhaps next ask me, is, at what point the differentiation of new-formations really begins. You will remember that, according to our views the great majority of new-formations have their origin in connective tissue or parts equivalent to connective tissue, and that the first rudiments of all new-formations are nearly of the same nature, and that in particular the divi
NOMENCLATURE OF NEW-FORMATIONS. 4G3
sion of the nuclei, their multiplication, and the final division of the cells shew themselves in nearly all new-formations, in the benignant as well as in the malignant, in the hyperplastic as well as in the heteroplastic ones, in the selfsame manner. Unquestionably, however, this similarity of nature is transitory; it is not long before some one characteristic feature displays itself in each individual structure, whereby we are enabled distinctly to recognize its nature.
With regard to this question of the criteria of newformations, no agreement in opinion has indeed even at the present moment been come to, and here too therefore it is incumbent upon me now to shew how I have arrived at my views which in many respects so widely differ from those generally held, and for what reasons I have deemed myself obliged to quit the beaten track.
The names which have been bestowed upon individual new-formations, have, as you know, often been based pretty much upon accidental peculiarities, and not so very unfrequently selected in quite an arbitrary manner. The attempts to establish a regular nomenclature, which were formerly made, were really only based upon the consistence of tumours, reasons for classification having been derived from the circumstance that the substance of new-formations was found to be sometimes hard, at others soft, fluid, pultaceous, gelatinous, &c, and thus meliceris, atheromata, steatomata, scirrhi &c. were separated from one another. It is self-evident that the ideas which are now attached to several of these things must be done away with, if it be wished to understand the original meaning of these designations. When the presence of an atheromatous process is now-a-days spoken of, something is meant thereby of which the old observers were far from having any idea. When the tumour anatomists of the present day labour hard to revive the name steatoma and would have