Page:Encyclopædia Britannica, Ninth Edition, v. 18.djvu/289

P A R P A K 271 its microscopic characters beyond the presence of the young nema- todes. These are also present in the chylous urine. Sometimes the discharge of lymph takes place at one or more points of the surface of the body, and there is in other cases a condition of use- void elephantiasis of the scrotum, or lymph-scrotum. More or less of blood may occur along with the chylous fluid in the urine. Both the chyluria and the presence of filarice in the blood are curiously intermittent ; it may happen that not a single filaria is to be seen during the daytime, while they swarm in the blood at night, and it has been ingeniously shown by Dr S. Mackenzie that they may be made to disappear if the patient sits up all night, reappearing while he sleeps through the day. Dr Mauson of Amoy has proved that mosquitoes imbibe the embryo filaripe from the blood of man ; and that many of these reach full development within the mosquito, acquiring their freedom when the latter resorts to water, where it dies after depositing its eggs. Mosquitoes would thus be the intermediate host of the filarise, and their introduction into the human body would be through the medium of water. Dracontiasis or Guinea-worm. Filaria incdincnsis, or Dracun- culus, or Guinea-worm, is a very long filarious nematode like a horse hair, whose most frequent habitat is the skin of the legs and feet. It is common on the Guinea coast, and in many other tropical and subtropical regions, and has been familiarly known since ancient times The condition of dracontiasis due to it is a very common one, and sometimes amounts to an epidemic. The black races are most liable, but Europeans of almost any social rank and of either sex are not altogether exempt. The worm lives in water, and, like the Filaria sanguinis hominis, appears to have an intermediate host for its larval stage. It is doubtful whether the worm pene trates the skin of the legs directly ; it is not impossible that the intermediate host (a Cyclops) which contains the larvre may be swallowed with the water, and that the larvae of the Dracimculus may be set free in the course of digestion. Endemic Hxmatnria and Calculus due to Distoma hsematobium. D. h&matobium is a tiematode or fluke-worm, which is exten sively parasitic in man in northern and southern Africa in the former along the Nile, and in the latter mostly on a narrow belt of the Natal coast. The parasites live mostly in the blood-vessels of the intestine and of the urinary bladder, whence they reach the mucous membranes ; and the most remarkable effects of their para sitism are bleeding from the surface of the bladder and the forma tion of ura tic and phosphatic calculi around the clusters of eggs deposited by the Distoma. The mode of access to their human habitat is still uncertain. Literature. The more special memoirs nrc Ponfick, Die Actinomyttte det Jtfenschen, eine neue liijectionskranklieit (plates, Berlin, 1882); Leuckart, Unter- sucli. iiber Trichina spiralis (plates, Leipsic, 2cl eel., 18fif>); Virchow, Darstellung der Lt-hre von den Trichinen (plate, Berlin, 2d ed., 1864); Long. De 1 andmie des mineurs clu Gothard, caused par 1 Ankylostome Uuoddnal," in Trans. Internal. Med. Congr., 1881, i. p 437, and papers quoted in llirscli; T. K. Lewis, On a Jlaimatozoon inhabiting Human Blood, its relation to Chyluria, <tc., Calcutta, 1872; Manson, The Filaria Sanguinis Hominis, &c. dilates, London, 1884); S. Mackenzie, "Case of h larial liaamuto chyluria," in Trans. Path. Soc. Lond., 1882, p. 394 ; see also Hirsch, Historisch-geographische Pathologic, vol. ii., Stuttgart, 1883 (English translation). (C. C.) PARC/E. See FATES, vol. ix. p. 49. PARCHMENT consists of skins of various animals, unhaired, cleaned, and dried so as to form sheets of uniform thickness suitable for writing upon and for the numerous other purposes to which such preparations are devoted (see PALEOGRAPHY, p. 144). The skins employed for parchment are principally those of sheep, lambs, and calves; but goat and ass skins are similarly dressed for special purposes. The preliminary unhairing and cleaning of the skins are effected as in the leather manufacture (see LEATHER, vol. xiv. p. 380). In their moist flexible condi tion the unhaired skins are tightly and uniformly stretched over a wooden frame termed a herse, and on the flesh side they are carefully gone over with a semicircular fleshing knife which removes all adherent flesh. The grain side is also gone over to clean the surface and squeeze out a proportion of the absorbed moisture. Ordinary binder s parchment and drum-head parchment need no further pre paration, but are simply allowed to dry gradually on the frames on which the skins are stretched. But fine parchment for writing and vellum are powdered with chalk on the flesh side and carefully rubbed with- fine pumice stone till a delicate uniform velvety surface is raised. All inequalities on the grain side are also re moved by paring and rubbing with fine pumice. Stout vellum is made from calf skins, and ordinary qualities from split sheep skins ; for drum heads, tambourines, and like applications goat and calf skins are used, and it is said that wolf skins yield the best drum heads. Veyetable Parchment, or parchment paper, is a modified form of paper produced by chemical treatment, having considerable similarity to ordinary animal parchment. It is prepared by acting on ordinary unsized paper with dilute sulphuric acid, and immediately washing away all trace of acid. Paper so treated will be found to have undergone a remarkable change : the porous intertexture of cellulose composing unsized paper will have expanded and agglutinated, forming a homogeneous surface, translucent, horny, and parchment-like ; it will have acquired about five times the strength of ordinary paper ; it will become soft and flaccid when steeped in water, to which, however, it is impervious ; and it is unaffected by boiling in water. The formation of vegetable parchment is due to a molecular change in cellulose when acted on by sulphuric acid, owing to which the substance is transformed into a starch-like body amyloid with simultaneous swelling of the fibres, which thereby soften and agglutinate. The preparation of vegetable parchment was patented in 18,57 by Mr W. E. Gaine, and machinery has been adapted for the manufacture. The paper to be acted on passes in a continuous web through a vat containing commercial sulphuric acid diluted with half its volume of water. In this it is immersed from five to twenty seconds at a tem perature of about 60 Fahr. It then passes in succession through pure water, next an ammoniacal solution to remove all acid, and finally again through water, after which it is dried and finished by passing between felted rollers and over heated polished metal cylinders. A similar effect is produced on paper by treating it with a syrupy solution of zinc chloride at from 120 to 212 Fahr. Vegetable parch ment has not realized all the expectations of it. It is most largely used as covers for preserve jars, bottles, &c., and to some extent for tracings of plans, charts, &c. PARDON is the remission, by the power entrusted with the execution of the laws, of the penalty attached to a crime. The right of pardoning is coextensive with the right of punishing. In a perfect legal system, says Beccaria, pardons should be excluded, for the clemency of the prince seems a tacit disapprobation of the laws (Dei Dehtti e delle Pene, ch. xx.). 1 In practice the prerogative is extremely valuable, when used with discretion, as a means of adjust ing the different degrees of moral guilt in crimes or of rectifying a miscarriage of justice. By the law of England pardon is the sole prerogative of the king, and it is declared by 27 Hen. VIII. c. 24 that no other person has power to pardon or remit any treasons or felonies what soever. This position follows logically from the theory of English law r that all offences are breaches of the king s peace. Indictments still conclude with a statement that the offence was committed " against the peace of our lady the queen, her crown and dignity." The crown by pardon only remits the penalty for an attack upon itself. The j prerogative is in modern times exercised by delegation, the crown acting upon the representation of the secretary of state for the home department in Great Britain, of the ! lord lieutenant in Ireland. The prerogative of the crown j is subject to some restrictions. (1) The committing of a 1 See further, on the ethical aspect of pardon, Montesquieu, Esprit des Lois, bk. vi. ch. 21; Beutham, Princijjlcs of Penal Law, bk. vi. ch. 4.