PEMPHIGUS, or POMPHOLYX, a skin disease which is characterized by an eruption of large vesicles, filled with serous fluid, and known as bullie. The disease occurs both in acute and in the chronic form. In a mild case of acute pemphigus, bullie, or blisters, from the size of a pea to that of a chestnut, ap pear in succession (chiefly on the ex 'remities), and having continued three or four days break, form a thin scab, and soon heal, unaccompanied with febrile or inflammatory symptoms. In severe cases there is considerable constitutional disturbance, the bullie are larger, and the scabs heal with difficulty. The chronic form differs mainly from the acute by its prolonged continuance. The acute variety chiefly affects children, and has been ascribed to dentition, errors of diet, etc.; while the chronic form chiefly attacks aged persons, and is probably due to debility and impaired nutrition.
PEN, an instrument for writing with a fluid. The metallic stilus for the pro duction of incised letters was probably the earliest writing implement. It was used by the Romans for writing on tab lets coated with wax; but both they and the Greeks also used what is the true an cient representative of the modern pen, namely, a hollow reed, as is yet common in eastern countries. It has been as serted that quills were used for writing as early as the 5th century A. D. In Eu
rope they were long the only writing im plements, the sorts generally used being those of the goose and swan. Up till the end of the first quarter of the 19th cen tury these formed the principal material from which pens were made. In 1803 Wise produced steel pens of a barrel form, mounted in a bone case for carry ing in the pocket. Joseph Gillott com menced the manufacture about 1820, and succeeded in making the pen of thinner and more elastic steel, giving it a higher temper and finish. Mr. Gillott was fol lowed into the same field by Mr. Perry and others, and their improvements re duced the cost and raised the quality. Cast-steel of the finest quality is used in the manufacture, and the various opera tions are performed by cutting, stamping and embossing apparatus. Birmingham was the first hom. is still the prin cipal center of the steel-pen industry. Gold pens tipped with minute particles of iridium are now in extensive use, and a good one will last for years. Fountain pens and penholders, to carry a consid erable supply of ink and to discharge it in an equal manner, were invented by Joseph Bramah.