Page:EB1911 - Volume 21.djvu/363

 medieval versions of Phaedrus and their derivatives see L. Roth, in Philologus, i. 523 seq.; E. Grosse, in ''Jahrb. f. class. Philol.'', cv. (1872), and especially the learned work of Hervieux, Les Fabulistes latins depuis le siècle d’Auguste jusqu’à la fin du moyen âge (Paris, 1884), who gives the Latin texts of all the medieval imitators (direct and indirect) of Phaedrus, some of them being published for the first time.

 PHAER (or ), THOMAS (1510?–1560), English translator of Virgil, was educated at Oxford and at Lincoln’s Inn. He published in 1535 Natura brevium, and in 1543 Newe Boke of Presidentes. He says on the title-page of his version of the Aeneid that he was “solicitor to the king and queen’s majesties, attending their honourable council in the marches of Wales.” He settled at Kilgarran in Pembrokeshire, and combined the study of medicine with his legal practice. He wrote several medical works, and was admitted M.D. of Oxford in 1559. He contributed to Sackville’s Mirrour for Magistrates, “Howe Owen Glendower, being seduced by false prophecies, toke upon him to be Prince of Wales.” In 1558 appeared The Seven First Bookes of the Eneidos of Virgil converted into English Meter. He had completed two more books in April 1560 and had begun the tenth, but he died in the autumn of that year, leaving his task incomplete. The translation was finished by Thomas Twyne in 1584. Phaer’s translation, which was in rhymed fourteen-syllabled lines, was greatly admired by his contemporaries, and he deserves credit as the first to attempt a complete version, the earlier renderings of Surrey and Gawain Douglas being fragmentary although of greater poetic value.

 PHAËTHON (Gr. , shining, radiant), in Greek mythology, the son of Helios the sun-god, and the nymph Clymene. He persuaded his father to let him drive the chariot of the sun across the sky, but he lost control of the horses, and driving too near the earth scorched it. To save the world from utter destruction Zeus killed Phaëthon with a thunderbolt. He fell to earth at the mouth of the Eridanus, a river of northern Europe (identified in later times with the Po), on the banks of which his weeping sisters, the Heliades, were transformed into poplars and their tears into amber. This part of the legend points to the mouth of the Oder or Vistula, where amber abounds. Phaethon was the subject of a drama of the same name by Euripides, of which some fragments remain, and of a lost tragedy of Aeschylus (Heliades); the story is most fully told in the Metamorphoses of Ovid (i. 750–ii. 366 and Nonnus, Dionysiaca, xxxviii). Phaëthon has been identified with the sun himself and with the morning star (Phosphorus). In the former case the legend is supposed to represent the sun sinking in the west in a blaze of light. His identification with the morning star is supported by Hyginus (Astron. ii. 42), where it is stated that the morning (and evening) star was the son of Cephalus and Eos (the father and mother of Phaëthon according to Hesiod, Theog. 984–986). The fall of Phaëthon is a favourite subject, especially on sarcophagus reliefs, as indicating the transitoriness of human life.

 PHAGOCYTOSIS (Gr. , to eat, devour, and  , cell). Many cells of the body possess the property of engulfing particles, a character to be associated with their power of performing amoeboid movement. This property is termed phagocytosis. Primarily this phagocytic power was simply the means by which the cell took within its cell body food particles which were ultimately digested and assimilated. In the higher organisms, however, this property has been developed for different purposes, and in pathology at the present day a meaning wider than that above given is often included in the term. The particle having been taken into the cell, one of three things may happen. (1) The particle may consist of digestible material, in which case the cell secretes a digestive fluid, a food vacuole is formed, the particle is gradually dissolved by the secretion and the products absorbed into the cell substance. (2) The particle may be indigestible, in which case it is retained within the cell body for a time and ultimately discharged. The particle englobed may comprise almost any material, but if it is to serve as a food it must be of animal or vegetable origin. At the time of ingestion it may be dead or living. In the case in which it is living the organism is first killed and then digested, or (3) the organism may prove resistant, in which case it may multiply and finally destroy the cell, when a number of organisms are set free. This is one of the means by which, in the higher organisms, a local infection may become distributed through the organism. The digestion effected within a cell is fermentative in character Thus a proteolytic ferment has been prepared from the bodies of amoebae—the ferment possessing fairly active properties both in acid, neutral or alkaline media, but especially in the latter.

In studying the process of phagocytosis generally much information may be gained as to its general characters by the study of the processes of intracellular digestion in the simpler Invertebrates, a study largely extended by Metchnikoff and his co-workers in the elaboration of Metchnikoff’s view of the nature of immunity. Thus, to take an instance from the sponges. Food substances, in the form of minute organisms, which have penetrated the pores of the sponge are seized by the ciliated or amoeboid cells lining those spaces, and are then killed and digested. In this case also the process of digestion is proved to be fermentative. It is readily understandable that we should find such cells on the external surface of an organism or on the surface lining the alimentary tract, particularly in the latter position. But in addition there are many cells within the body in which phagocytic power is retained and markedly developed. Such cells may be fixed or wandering cells. They are employed for removing foreign material or debris which may occur within a tissue. For instance, as the result of an injury, inflammatory process, &c., cells and other structures of a tissue may be destroyed. One of the processes of repair consists in the removal of the resulting debris, which is effected by phagocytes. A similar process is seen with red blood corpuscles which may have escaped into a tissue through rupture of capillaries. Foreign particles accidentally gaining admission to a tissue are in many cases removed in a similar manner, e.g. soot particles which have passed through the respiratory surface are then largely removed by phagocytes and carried to the bronchial lymphatic glands. Very commonly living organisms effect an entrance through wound surfaces, the alimentary surface, &c., and one of the processes employed for their destruction and removal is that of phagocytosis.

As an illustration of the removal of foreign red blood corpuscles we may take the experiments of Metchnikoff in which a small drop of defibrinated blood of the goose was injected under the skin of a snail. The corpuscles quickly spread through the haemolymph of the snail, which by itself, however, effects no change in them. At the end of several hours examination shows that the leucocytes of the snail have englobed a large number of the red corpuscles. The following day intact corpuscles can still be found in the haemolymph, but the major number have already been devoured by the leucocytes. When taken up by a phagocyte the red corpuscle becomes round and its wall permeable. A vacuole is formed around the corpuscle, in which dissolved haemoglobin can be seen; a part of this haemoglobin also passes into the nucleus of the red corpuscle, proving that it too has been profoundly altered. Many of the nuclei are discharged. After some time the only parts of the corpuscle remaining are pieces of the nucleus and the peripheral layer of the corpuscle. Frequently the phagocytes, after having devoured one or several red corpuscles, themselves become a prey to their fellows. Analogous changes are observed in the tissues of a mammal when blood which has been extravasated is being removed, e.g. after a bruise. The first effect of the haemorrhage is an exudative inflammation, during which leucocytes arrive in large numbers and engulf the corpuscles. In the process of digestion which follows the haemoglobin is altered and new pigments formed from it. In mammals this pigment is dark red or brownish, in the pigeon it is green. Finally the corpuscles are completely digested. Analogous phenomena may be observed