The refuse of the cotton and flax mills, and numerous other substances of a like character, are now worked up as papier-mache, and the manufactured articles formed of them are indistinguishable from those prepared directly from paper.
=PAPIN'S DIGESTER= is a strong, closed, iron vessel, in which water can be heated above 212 F., thereby acquiring a temperature that adds considerably to its solvent powers. This apparatus is put to many useful applications in the arts, of which one is the speedy extraction of gelatin from the earthy matter of bones. The bones may be boiled for hours at 212 without any such effect being produced. The high temperature acquired by the water is effected by the confinement of the steam, the internal pressure of which can be regulated by means of a safety valve attached to the vessel. By this arrangement the water may be kept at any uniform temperature above 212 at pleasure. Professor Junichen[91] recommends the use of the digester for the purpose of boiling meat and other food. It appears from the author's experiments that the time for cooking various articles of daily consumption is much shorter when effected under strong pressure, while a great saving of fuel is also effected.
[Footnote 91: 'Chemical News.']
=PAPY'RIN.= See PAPER (Parchment).
=PAR'ACHUTE.= In aerostation, an instrument or apparatus having for its object to retard the descent of heavy bodies through the air. The only form of parachute which has been hitherto adopted with success is that of the common umbrella when extended. The materials of which the apparatus is made are canvas and cord, both light but strong, and carefully put together. The car to contain the adventurer resembles that of the balloon, only smaller.
It is estimated that a circular parachute, to descend in safety with an adult, weighing, with the apparatus, 225 lbs., must have a diameter of at least 30 feet. Its terminal velocity would then be at the rate of 12 to 13 feet per second, or about 6-1/2 miles per hour; and the shock experienced on contact with the earth would be equal to that which the aeronaut would receive if he dropped freely from a height about 2-1/2 feet.
Several descents from balloons, after they have acquired a great elevation, have been effected without accident by means of parachutes.
Unfortunately, however, any want of integrity in the machine, or any accident which may happen to it after its detachment from the balloon, is irreparable and fatal.
=PARACYAN'OGEN.= The brown solid matter left in the retort when cyanide of mercury is decomposed by heat. It is isomeric with cyanogen.
=PARAFFIN.= _Syn._ TAR-OIL STEARIN. This remarkable hydrocarbon is one of the several substances discovered by Reichenbach in WOOD-TAR.
_Prep._ 1. (From WOOD-TAR. Reichenbach.) Distil beech-tar to dryness, rectify the oily portion of the product which is heavier than water until a thick matter begins to rise, then change the receiver, and moderately urge the heat as long as anything passes over; next digest the product in the second receiver, in an equal measure of alcohol of 833, gradually add 6 or 7 parts more of alcohol, and expose the whole to a low temperature; crystals of paraffin will gradually fall down, which, after being washed in cold alcohol, must be dissolved in boiling alcohol, when crystals of pure paraffin will be deposited as the solution cools.
2. (From COAL--James Young, Patent 1850.) The details of this process for obtaining paraffin and its congeners by the slow distillation of coal (preferably 'Boghead') are given in our article on PARAFFIN OIL. The solid paraffin is separated from the last products, or 'heavy oils,' by artificial cold; it is then melted and run into moulds.
3. (From RANGOON PETROLEUM--Patent.) In this process, which is worked by Price's Candle Company, superheated steam is employed as the heating agent. The paraffin, or 'BELMONTINE,' as it is called, is the last product which distils over.
4. (From PEAT.) The various processes which have been suggested for obtaining paraffin from peat, turf, &c., are similar in principle to Young's. The great point is to conduct the distillation at as low a temperature as possible.
_Prop._ A white, hard, translucent body, melting at 110 Fahr. and upwards, according to its source, and burning with a bright white flame.
It has great stability--sulphuric acid, chlorine, and nitric acid below 212 exerting no action upon it. Dr Anderson states that its composition and properties vary with the source from which it is derived. With respect to the melting point, this variation is very remarkable. Thus, Young's paraffin, from Boghead coal, melts, according to the observations of Dr Anderson, at 114, while that from Rangoon petroleum ('belmontine') melts at 140, and that from turf at 116.
_Uses._ Paraffin is now largely used for making candles, for which purpose it is specially adapted, being a most elegant substance, and surpassing all other candle materials, even spermaceti, in illuminating power. Its property of not being acted upon by acids or alkalies renders it suitable for stoppers for vessels holding chemical liquids; also for electrotype moulds. It is not acted upon by ozone, so that it has been employed with great advantages in experiments on this body for rendering air-tight the joints formed by the union of glass tubes. As it contains no oxygen, it might be employed to protect oxydisable metals like sodium and potassium from contact with the air. One use of paraffin candle-ends will commend them to the ladies of the household--a small piece of paraffin added to starch will be found to give a gloss and brilliancy of surface to the starched linen that can be obtained by no other addition.
=PARAFFIN OIL.= See OILS.
=PARAL'YSIS.= _Syn._ PALSY. A loss or considerable diminution of power of voluntary motion, or functional action, of any part of the body. In its most usual form one side only of the body is affected. It not uncommonly seizes the lower extremities, or all parts below the pelvis; sometimes the arms only; and occasionally a part, as one side of the face, one eyelid, the tongue, or the muscles of deglutition. In these cases the speech frequently becomes indistinct and incoherent, and the memory and judgment impaired, whilst the distorted features assume a more or less revolting aspect.
The causes of paralysis are various. It may be occasioned by pressure on particular parts of the brain, the spinal marrow, or the nerves; by poisons, the long-continued use of sedatives, local injuries, the sudden suppression of profuse and habitual evacuations, and by whatever tends to greatly relax or enervate the system. It may also be a consequence of an attack of apoplexy, or it may be symptomatic of other diseases, as scrofula, syphilis, and worms. When it is of a distinctly local character it may arise from excessive use or undue employment of the part or organ.
That of old age is, probably, a mere consequence of the failing nervous energy of the system being unequally distributed.
Palsy usually comes on with a sudden and immediate loss of the motion and sensibility of the parts; but in a few instances it is preceded by a numbness, coldness, and paleness; and sometimes by slight convulsive twitches. If the disease affects the extremities, and has been of long duration, it not only produces a loss of motion and sensibility, but likewise a considerable flaccidity and wasting away of the muscles of the parts affected.
When palsy attacks any vital part, such as the brain, heart, or lungs, it soon terminates in death.
The treatment of paralysis depends upon a careful consideration of its cause. The first object should be, as far as possible, to remove any compressing force, and to gradually arouse the torpid portion of the nervous system. In general, more or less depletion will be found beneficial, together with rather active purgation, and nervous stimulants, as ammonia, musk, &c. Blisters to the head and neck are also appropriate.
With the debilitated and aged, venesection must be avoided. Stimulant and rubefacient frictions and liniments, the vapour bath, and other like remedies, also frequently prove useful. In local attacks of the disease, as the loss of use of one of the hands, arms, legs, &c., no agent has proved so generally successful as voltaic electricity. For this purpose the current should be in one direction only, and continued uninterruptedly for some time daily. When the direction of the current is alternate, with slight shocks, as in the common coil machine, this agent is of doubtful utility, except for occasional use. In all cases medical aid should be sought as early as possible.
=PARANAPH'THALIN.= _Syn._ ANTHRACEN. See ANTHRACEN.
=PARAPEC"TIN.= See PECTIN.
=PAR'ASITES.= The parasitical animals that infest the human body are referred to under the heads ACARI and PEDICULI.
=Parasites, Human.= The following is a list of the principal parasites infesting man. It is extracted from the 'Dictionary of Hygiene,' of Wynter Blyth, who states that he has arranged it, with some slight alterations, from a table in Dr Aitken's 'Science and Practice of Medicine.' The two first divisions include animal parasites, the third vegetable ones. No. 1, or _Entozoa_, are animal parasites found inside the human body; No. 2, those found outside; No. 3, consisting of vegetable parasites, comprises _Entophyta_ and _Epiphyta_, the former existing in the interior, and the latter on the exterior of the human body. Some of the principal parasites have already been described and figured in these pages.
I. _Entozoa._
Acephalocystis endogena, _liver_.
" multifida, _brain_.
Anchylostomum, seu Sclerostoma duodenale, _intestines_.
Anthomia canicularis, _intestines_.
Ascaris alata "
" lumbricoides "
" mystax "
Bilharzia seu Distoma haematobia, _portal and venous system_.
Bothriocephalus cordatus, _intestines_.
" latus "
Cysticercus cellulosae, seu telae cellulosae (C. of Tenia solium), _muscles_.
Cysticercus of Taeniae marginata (C. tenuicollis), _intestines_.
Dactylius aculeatus, _urinary bladder_.
Diplosoma crenatus.
Distoma seu Distomum crassum, _duodenum_.
" hepaticum seu Fasciola hepatica, _gallbladder_.
" heterophryes, _intestines_.
" lanceolatum, _hepatic duct_ " oculi humani seu ophthalmobium, _capsule of crystalline_.
Ditrachycerus rudus, _intestines_.
Echinococcus hominis (hydatid of Taenia echinococcus), _liver, spleen, and omentum_.
Filaria bronchialis seu trachealis, _bronchial glands_.
" seu dracunculus medinensis, _skin and areolar tissue_.
" sanguinis hominis, _blood_.
" oculi seu lentis, _eye_.
Hexathrydium pinguicola, _ovary_.
" venarum, _venous system_.
Monostoma lentis, _crystalline_.
strus hominis, _intestines_.
Oxyuris vermicularis, "
Pentastoma constrictum, _intestines and liver_.
" denticulatum, _intestines_.
Polystroma pinguicola, _ovary_.
" sanguicola seu verarum, _venous system_.
Spiroptera hominis, _urinary bladder_.
Strongylus seu Eustrongylus bronchialus, _bronchial tubes_.
" seu Eustrongylus gigas (Acarus renalis), _kidney and intestines_.
Taenia acanthotrias, _intestines_.
" elliptica, "
" flavopuncta, "
" lophosoma, "
" mediocanellata, "
" nana, _intestines and liver_.
" solium, _intestines_.
Tetrastoma renale, _kidney_.