MORBID ANATOMY.—The following morbid changes have been observed to occur in the thyroid ; (1) It may be affected with com mon inflammation. (2) It may be variously altered by unhealthy or perverted action of its own glandular structure. (3) It may be the seat of adventitious formations. (4) Its vessels may become remarkably enlarged, as in the so called aneurism by anastomosis.
Professor Hasse gives the following description of inflammation occur ring in the thyroid. " It is rare, but may at tack the organ either when healthy, or when enlarged by previous disease. Its course is more frequently chronic than acute. Within a very brief interval the gland often swells considerably, becomes very bloodshot, tense, and painful, its texture softened and friable, assuming at first a brown red, and ultimately a dingy gray colour. The morbid anatomy of this grade of inflammation is but imper fectly known ; that of the suppurative stage has been more frequently observed, and more fully described. Either separate ab scesses form, or else the entire gland is converted into pus. Under favourable cir cumstances the abscess opens externally through the skin. There are, however, ex amples of its obtaining vent through the oesophagus, and determining a protracted fistula of the gullet,* or of its discharging itself into the trachea, and producing death by suffocation.} After evacuation of the pus, together with numerous shreds of dead cellular tissue, the tumour collapses ; the gland on the side affected shrivels into a hard, cellulo filamentous knot, which adheres firmly to the skin and to the surrounding parts. Some times the shrivelling of the one gradually brings on wasting of the other lobe.' Alterations of Structure. — Under the se cond head may be included hypertrophy of the thyroid, or some enlargement without appreciable change of texture. This variety," Prof. Hasse states, " is frequent, and for the most part inconsiderable." It probably depends merely on distension of the glan dular cavities by their accumulated secre tion. This change is almost wholly "confined to youth, and is frequent about the age of puberty in both sexes,— more so, however, in the female." " Alternatives of increase and decrease are especially apparent in this kind of bronchocele, enlargement being most con spicuous at the approach of the menstrual period." This form, though it may be called hypertrophy, is not quite strictly so desig nated, as there is no formation of new glandu lar tissue, but only distension of the original cavities, by an increased quantity of secretion.
" Melicerous degeneration of the thyroid is one of the most frequent forms. It occurs at all ages, and is uniformly attended with intu mescence. It may involve the organ in whole or in part. In the former case the component granules (or vesicles) are found unusually and unequally enlarged, and transformed into sepa rate cells filled with a tenacious, viscous, jelly like substance, of the colour of honey. The entire part is hard, nearly bloodless, and but loosely coherent with the surrounding parts. Where, as frequently happens, only certain portions are disorganized, these form spherical tumours varying in size, and imbedded clearly in the healthy structure. They present a brownish or yellow colour, and the consistency of jelly or of melted glue. Sometimes they appear as an opaque, reddish, soft, or even lardaceous, swelling. In general but few blood vessels are visible in this goitre, although it may now and then be associated with ex uberant vascular growth." The foregoing description is quoted from the translation by the Sydenham Society of Professor Hasse's work. He does not, how ever, seem to notice sufficiently, under this head, the variety of matters which are found in the enlarged glandular cavities. Cretaceous matter, either in a pulverulent state, or form ing hard ossiform amasses, I believe often occurs, and in Prep. 1498, of the Patholo gical collection in the Museum of the College of Surgeons, there is seen a quantity of solid white substance, either opaque and soft, or transparent, firm and chondroid, which oc cupies the larger cavities, the majority being filled with a transparent jelly-like material ; some also with cretaceous matter. One in
teresting instance, probably belonging to this class, is quoted in the Cyclop. of Pract. Medi cine from De Igen :—" In cadavere horren dam mole thyroideam nactus, publice dissecui. Mecum auditores mirabantur, null= fere gen us tumorum dari, quip in bile soli thyroidea in veniretur. Hic enim steatoma, ibi atheroma, alio in loco purulentus tumor, in alio hyda trios, in alio erat coagulatus sanguis, fluidus fere in alio, imo hint glutine loculus plenus crat, alibi calce cum scbo 'nista." I may mention here the results of micro scopic examination of a specimen of this form of enlarged thyroid, for the opportunity of making which I am indebted to the kind ness of the medical officers of St. George's Hospital. The gland was greatly enlarged ; its surface somewhat nodulated. A sec tion displayed a number of cavities visible to the naked eye, some of which were circular, others elongated, and as it were compressed. Many of them were about the size of a large pin's head; some however, much more capa cious. The majority were filled with a slightly opaque, firm, gelatinous material ; but some (the larger) with cretaceous or ossifortn matter, and some also with a reddish material. The intervening structure in several places appeared tolerably natural ; but even in this, on close in spection, enlarged vesicles were perceptible. The areolar tissue separating the lobes of the gland was hypertrophied, and formed whitish septa! bands. Under the microscope it was seen that the vesicles were generally enlarged. They were found of all sizes, from those that were distinctly visible to the naked eye, or still larger, down to the natural size. Their walls were somewhat but not uniformly or very greatly thickened. The homogeneous envelopes presented, generally, somewhat of a fibrous appearance. The greater number of the cavities were distended with a transparent, feebly refracting, structureless, material, in which were numerous small irregularly shaped particles of higher refracting power. This material resembled, almost exactly, the normal secretion in appearance, and, like it, was free in the cavity of the vesicles. In these vesicles there was very little trace of epithelium, only some small, and few, non-nucleated corpuscles ; but in other vesicles the epithelium was so abundant, that it completely occupied the cavity. It was in no respect different, except as to quantity, from its healthy condition, con sisting of mere nuclei and interposed granular matter in no great abundance. In some of the vesicles there were large and beautiful crystals of more or less perfect octohedral form. These were either oxalate of lime or triple phosphate. One prodigiously enlarged vesi cle contained a mass of calcareous matter, very firm and dense throughout, but most in its central and peripheral parts. In the latter situation there were numerous masses of ossi form substance, of yellowish semi-transparent aspect. On crushing these, no bone lacunte could be discerned in the fragments. They dis solved freely with strong effervescence in nitric acid, leaving an homogeneo-fibrous basis substance, which often exhibited a greenish yellow tint. The material, thus proved to be of cretaceous nature, contained, mingled with it, numerous tablets of cholesterine. One small reddish mass, occupying the cavity of a vesicle, was found to consist almost wholly of blood globules and their detritus, and thus seemed to be the result of haemorrhage. Another opaque whitish mass did not effervesce with nitric acid, and was therefore not cretaceous ; it consisted of epithelial nuclei mingled with peculiar, and rather abundant, granular matter. In the above account it is worth noticing that no cells were found ; the epithelium retained its natural appearance ; also the matter distend ing the greater number of the cavities resem bled exactly, so far as the eye could judge, the natural secretion ; and lastly, that in some in stances there was an accumulation of unaltered epithelium and not of the secretion. This last fact is of some importance with respect to the exact nature of the function discharged by the epithelium.