Primarily, the parenchymatous goitre would seem to be an overgrowth of the gland with overactivity, although such overgrowth may eventually give place to atrophy and inactivity of the specific glandular substance. It is very suggest ive that, in a large proportion of cases where the goitre is not of too long de velopment and is of the parenchymatous type, the iodine treatment has for long years been found to give good results. We are, in short, only just now seeing the beginning of a knowledge of the rela tionship of parenchymatous disturbances in the thyroid to disturbances of the gen eral body-metabolism, and at the present we can do little more than carefully note the nature of the anatomical changes of the organ, without being in any way sure of their bearing.
In the study of the histology of the vascular system of thyroid in goitre the author has examined twenty-eight glands taken from subjects varying in age from a foetus of the fourth month to an adult of GS years. Death in these cases was due to a variety of causes. In glands containing goitrous nodules ar teries were found in which there were well-marked proliferations of the endo thelium in localized areas, forming bud like projections. In one specimen these proliferations frequently occluded the artery. The groups of cells forming these buds may cause little or no pro jection of the intim. but may develop outwardly at the expense of the mus cular coat. The size of the buds varies much within certain limits.
As buds have been found containing colloid, they would seem to have the power of producing this material. The larger arteries are almost or altogether free from these changes. R. M. Horne (Lancet, Nov. 20, '92).
Goitre-formation apparently begins by a growth of processes of the normal glandular epithelium. The first clearly visible beginning of the nodular goitre consists of single processes of differen tiated epithelium in the secondary lobules. These processes gradually sup plant, metaplastically, the normal tissue of a secondary or even a primary lobule. The lobules thus changed form, as they increase in volume and supersede the surrounding tissue, the smallest true goitrous nodules. Neighboring lobules changed in this way form multilocular goitrous nodules, either blending by a growth through the intervening septa or flattening where they come in contact. Finally, the outer compressed lobules surround the central, more vigorously growing ones like a shell. The metaplas
tie growth ends when the boundary of the primarily-affected lobnle is reached, growth then taking place by displace ment of the surrounding tissue. Diffuse goitre consists of a uniform proliferation in all the lobules. Nodular goitre arises through a variation in the vitality of neighboring parts. There exist a great variety of intermediate forms. T. Hitzig (Schmidt's Jahrbucher, July, .94).
The most frequent fact observed in ten cases was the presence of fine granu lar matter in the follicles, and in such quantity that in some cases it surpassed that of the homogeneous colloid masses. These granulations are of the greatest importance in explaining the formation of colloid matter, for they form one of the preliminary stages, and the progress ive transformation from one to the other may often be seen in the same follicle. In this transformation there is not only a modification of density, but a change of color also. The origin of the granular matter is located in certain large round or oval elements, larger than the epithe lial cells, with pale protoplasm, but formed by the same fine granular masses as the rest of the follicular contents which surround it. These are considered to be only modifications of epithelial cells. The special point of interest in this process is the complete absence of homogeneous drops, of irregular balls or masses, giving birth to colloid matter by their confluence. The formation of col loid substance in goitre should, there fore, be considered as a purely degener ative process. Reiubach (Beitrilge zur path. Anat., etc., B. Id, p. 596, '95).
Prognosis.--Upon the whole, save in malignant forms of the condition, the prognosis must be regarded as favorable. Even where no steps are taken to arrest the growth, it is a matter of common observation in goitrous districts that persons for long years may bear tumors of great size without pronounced ill effects. Occasionally, however, severe, not to say fatal, respiratory disturbances may supervene in those with compara tively-small goitres, either from haemor rhage into the gland or from develop ment of nodules in such a direction as to press on the trachea. Lucke has noted that occasionally after acute febrile dis ease a goitre may entirely disappear, and this vascular form, if of recent develop ment, may spontaneously diminish in size.