Pemphigus

PEMPHIGUS, a skin disease, in which large blebs appear, on a red base, containing a clear or yellowish fluid; the blebs occasion much irritation, and when they burst leave raw ulcerated surfaces. The disease is principally known in unhealthy or neg lected children. A variety of the malady pemphigus foliaceus, affects the whole body, and gradually proves fatal. Pemphigus of an acute septicaemic type may occur in butchers or those who handle hides. In chronic pemphigus, streptococci have been found in the blebs, and improvement has followed injection of a vaccine of streptococci.

PEN, an instrument for writing or for forming lines with an ink or other coloured fluid (Lat. penna, a feather, pen). The earli est writing implement was probably the stilus (Gr. 'pacPis), a pointed bodkin of metal, bone or ivory, used for producing in cised or engraved letters on boxwood tablets covered with wax. The calamus (Gr. 'cactilos) or arundo, the hollow tubular stalk of grasses growing in marshy lands, was the true ancient repre sentative of the modern pen ; hollow joints of bamboo were sim ilarly employed. An early specific allusion to the quill pen occurs in the 7th century writings of St. Isidore of Seville, but there is no reason to assume that it was not in use at a still more remote date. The quills still occasionally employed among Western com munities as writing instruments are obtained principally from the wings of the goose (see FEATHER). In 1809 Joseph Bramah de vised and patented a machine for cutting up the quill into sep arate nibs by dividing the barrel into three or even four parts, and cutting these transversely into "two, three, four and some into five lengths." Bramah's invention first familiarized the public with the appearance and use of the nib slipped into a holder. But a more distinct advance was effected in 1822, when .J. I. Hawkins and S. Mordan patented the application of horn and tortoise-shell to the formation of pen-nibs, the points of which were rendered durable by small pieces of diamond, ruby or other very hard substance, or by lapping a small piece of thin sheet gold over the end of the tortoise-shell.

Metal Pens.

Metallic pens, though not unknown in classical times—a bronze pen found at Pompeii is in the Naples museum— were little used until the i9th century and did not become com mon till near the middle of that century. It is recorded that a Birmingham split-ring manufacturer, Samuel Harrison, made a steel pen for Dr. Joseph Priestley in 5780. Steel pens made and sold in London by a certain Wise in 1803 were in the form of a tube or barrel, the edges of which met to form the slit, while the sides were cut away as in the case of an ordinary quill. Their price was about five shillings each, and as they were hard, stiff and unsatisfactory instruments they were not in great demand. To John Mitchell probably belongs the credit of introducing ma chine-made pens, about 1822, and James Perry is believed to have been the first maker of steel slip pens. In 1828 Josiah Mason,

who had been associated with Samuel Harrison in the manufacture of split rings, saw Perry's pens on sale in Birmingham, and after examining them saw his way both to improve and to cheapen the process of making them. He therefore put himself in communica tion with Perry, and the result was that he began to make barrel pens for him in 1828 and slip pens in 1829. Perry, who did much to popularize the steel pen and bring it into general use, in his patent of 1830 sought to obtain greater flexibility by forming a central hole between the points and the shoulders and by cutting one or more lateral slits on each side of the central slit ; and in 1831 an improvement, which consisted in forming elongated points on the nibs of the pens, was described by Joseph Gillott.

The metal used consists of rolled sheets of cast steel of the finest quality made from Swedish charcoal iron. These sheets, after being cut into strips of suitable width, annealed in a muffle furnace and pickled in a bath of dilute sulphuric acid to free the surface from oxidized scale, are rolled between steel rollers till they are reduced to ribbons of an even thickness, about inch. From these ribbons the pen blanks are next punched out, and then, after being embossed with the name of the maker or other marks, are pierced with the central perforation and the side or shoulder slits by which flexibility is obtained. After another an nealing, the blanks, which up to this point are flat, are "raised" or rounded between dies into the familiar semi-cylindrical shape. The next process is to harden and temper them by heating them in iron boxes in a muffle-furnace, plunging them in oil, and then heating them over a fire in a rotating cylindrical vessel till their surfaces attain the dull-blue tint characteristic of spring-steel elasticity. Subsequently they are "scoured" in a bath of dilute acid, and polished in a revolving cylinder. The grinding of the points with emery follows, and then the central slit is cut by the aid of two very fine-edged cutters. Finally, the pens are again pol ished, are coloured by being heated over a fire in a revolving cylinder, and in some cases are coated with a varnish of shellac dissolved in alcohol. An increasing quantity of pens today are plated with metal alloys which give them a silver-like finish and increased resistance to acids and atmospheric conditions. Birming ham was the first home of the steel-pen industry, and continues its principal centre. Manufacture on a large scale was begun in the U.S. about 1860 at Camden, N.J.

Metals other than steel have frequently been suggested by in ventors, those most commonly proposed being gold, silver, zinc, German silver, aluminium and aluminium bronze. The latest development, introduced in 1926, is the manufacture of pens made from stainless steel. These pens are highly resistant to the acids used in writing inks and are non-tarnishing under extreme climatic conditions. (See also FOUNTAIN PEN.)