The Renal Preparation At First Sight so much resembles the texture of the thyroid gland, and more particularly the goitred thyroid gland, as to render it impossible to discriminate between the two. Simon has directed attention to this in vol. xxx. of the ' Transactions of the Medical and Chirurgical Society.' Not only is the normal gland-vesicle of the thyroid gland identical with a cyst of corresponding size, but the development of new gland-vesicles in a goitre is identical with cyst development, and again the preternatural dilatation of the gland-vesicle - its so-called cyst-like degeneration - identical with a cyst outgrowing its microscopical proportions. Nay, the gland-vesicle betrays in its development the same anomalies as the cyst in its development as a sterile vesicle, or as a laminated cyst in its degeneration to a colloid sphere, and in its incrustation.

3. The same relations attach to cyst-formation in mucous membranes. In those of the stomach, the colon, the uterus, a morbid growth occurs, known by the term cell- or vesicle-polypus. It consists of an aggregation of from millet or hemp-seed to pea-sized cysts, broad-based, but mostly furnished with a neck, and commonly representing the head-like free extremity of a cylindrical prolongation of the mucous membrane. These cysts are developed in the texture of the mucous membrane, seldom exceed the aforesaid volume, but burst and evacuate their viscid, jelly-like contents upon the surface of the mucous membrane. Their fate, beyond this disruption and violence, I have been unable to ascertain. They probably give place to new ones. We may refer here to those bodies suspended by a pedicle of mucous membrane from the cervix uteri, and known as ovula Nabothi. These, though commonly received within the domain of physiology, in reality present a continuous cyst-formation, destroyed from time to time by disruption and evacuation. They occur, in like manner, on the mucous membrane of the renal pelves, and of the ureters.

But I have repeatedly observed millet, hemp, nay almost pea-sized cysts, in surpassing numbers in the mucous membrane of these urinary conduits. Some of them contained a flaky, inspissated, colloid moisture. In one instance, my attention was drawn to them, by the presence of little, roundish, naked, colloid pellets, in the urinary bladder.

Just as in physiological textures, so also in pathological parenchymata does cyst-formation occur. For example; in the textures of sarcoma and carcinoma, - giving rise to the family of cysto-sarcomata and cysto-carcinomata. Even the so-called carcinoma alveolare consists, mainly, in cyst-development.