ON

THE ANATOMICAL CHARACTERS

OF SOME

ADVENTITIOUS STRUCTURES,

BEING AN ATTEMPT TO POINT OUT THE RELATION BETWEEN THE MICROSCOPIC CHARACTERS AND THOSE WHICH

ARE DISCERNIBLE BY THE NAKED EYE.

BY THOMAS HODGKIN, M.D.

READ JUNE 13TH, 1843.

In the spring of 1829, I had the honour of laying before this Society the result of an inquiry in which I had then been for some years engaged, respecting the anatomical characters of a large and important group of adventitious structures. From that period to the present time, I have not ceased to embrace the opportunities which presented themselves, for continuing the same kind of research.

As I have already published some of the results which I have obtained, in my lectures on the morbid anatomy of the serous and mucous membranes, it is not my intention to trespass on the Society by a repetition of the details which may be found there.

My object, on the present occasion, is rather to endeavour to demonstrate the relation which some of the phenomena connected with these structures, which have been pointed out by able and distinguished observers, bear to those which have been noticed and described by myself, and to show that whilst our observations have been in some respects dissimilar in their kind, they are not, in their general results, to be regarded as clashing, or mutually opposed to each other, but that having been directed to different parts of the subject, they require to be united in order to render it complete.

In the course of this attempt, I shall, however, take the opportunity to reply to some objections which have been urged against my previous statements, and to record some further facts which have fallen under my observation.

My former communication merely claimed to be the announcement of the anatomical character of some of the structures referred to; the main object being to show their assumption of the type of compound serous cysts, the modifications of which I described as a preliminary step. I endeavoured to show, that whilst possessing this type, variously modified by the forms of the cysts, and the relative proportion of the solid to the fluid parts, there likewise existed great and important differences dependent on the material by which this form or type may be assumed, and the character and degree of vascular organisation which it receives. At that period, the very curious and important researches

regarding the function and development of nucleated cells had either not been made, or were generally unknown in this country; and microscopic inquiry, not being necessary to that part of the subject with which I was engaged, had not been undertaken by myself.

Shortly after, that learned and well-practised pathologist, Dr. Carswell, then Professor at the London University College, published, with illustrated plates, his views regarding the production of carcimonia, in which he subscribed his adhesion to that group of pathologists who refer the production of the adventitious structures in question to an error in the blood or lymph, and he adduced some remarkable instances in which a material, resembling that of the adventitious structure, was discovered in the interior of vessels. According to this view, as employed by the Professor to explain the formation of adventitious structures, the necessity for cysts, whether simple or compound, is dispensed with; and he employs an argument against their agency in the production, which makes it evident that my view has not been clearly understood. On this point he is followed by the learned Professor Grose, of the United States.

Perhaps the most laborious and longest sustained inquiry connected with this subject, has been that of my friend Francis Kiernan, whose practised eye and delicate manipulation must attach the greatest value to his researches. Their results have not yet been made public, but it is well known that they are

much admired by those to whom they have been communicated; and it is generally understood that they relate mainly to the mode of organisation, and the condition of the vessels belonging to the structures in question. I may therefore conclude, that they do not necessarily confirm or invalidate those observations to which my inquiry had led, though I conceive that, in many instances, they ought to facilitate its illustration.

In the autumn of 1838, I paid a transient visit to Berlin, where I had the pleasure of receiving from Professor Schwann a demonstration of the nucleated cells, pointed out by himself and Schleiden as performing an important and essential part in the formation of vegetable and animal tissues. I procured, at the same time, the important work of Professor Müller on the structure of cancer and other adventitious structures, which had then very recently appeared. I likewise inspected the preparations in the museum of the university, relating to this subject, which had been made by Müller himself, but, in the absence of the Professor, they contributed little to the explanation of his views, and presented nothing in refutation of my own. In this respect I laboured under a disadvantage, similar to that which Professor Müller himself experienced when visiting the collection at Guy's, when I had not the satisfaction of accompanying him.

The group of structures with which we are engaged, differs so widely from those which belong to the body in its healthy state, as to have obtained the distinction

of heterologue. Microscopic examination affords us the means of becoming acquainted with the most intimate structural peculiarities, and is therefore the counterpart of chemical analysis, which relates to the elements which enter into their composition.

The characters thus brought to light, which Professor Müller was, I believe, the first to point out, have very naturally arrested the attention of inquirers, from their intrinsic importance, and from the high authority of the Professor who noticed them. The most practised eyes, and the best instruments, have been employed in these observations, and the results obtained have been so generally in accordance, that, notwithstanding the doubts which are attached by some to microscopic inquiries, they may be received with confidence, although from the optical characters of the objects themselves, their examination is often difficult.

I may observe, that I have not only been on the alert to obtain specimens, but have been anxious to examine them in their most recent state, in order to avoid the changes which may be induced by decomposition, or by the influence of antiseptics employed to counteract it. I have likewise been desirous of having the concurrent testimony of other eyes beside my own; and my thanks are especially due to my friends, John Dalrymple, George Gulliver, Alexander Nasmyth, William Bowman, and Dr. Barry, who have favoured me in this respect, and whose excellent instruments have been employed as well as my own.