PNEUMATICS 



6205 



PNEUMONIA 



Bypass' 



one direction and sucked in the 

 other, being controlled from the end 

 towards which a number of tubes 

 converge t.g. in a cashier's office. 

 More commonly a separate tube 

 is provided for each direction. The 

 all-vacuum system is represented 

 by an explanatory diagram. Air is 

 constantly exhausted through pipes 

 O and I in the direction indicated 

 by'the arrows. To send from (A) to 

 (B), a carrier is entered at a. On 

 reaching (B) it 

 opens V 2 and 

 drops into re- 

 ceiver R*. To 

 return it, (B) 

 opens a flap V 3 

 and places it 

 in pipe I. It 

 forces its way 

 past valve V 1 , 

 which closes 

 automatically 

 behind it, and 

 falls into re- 

 ceiver R 1 . One 

 inward pipe 

 may serve as 

 a main for 

 branches I 2 , I s , 

 entering it at a 

 trailing angle ; 

 but there must 

 be a separate 

 pipe for 

 each " out " 

 station, unless 

 special auto- 

 matic switching apparatus is fitted. 

 In another system, used by the 

 British Post Office, compressed air 

 tubes take the carriers outwards, 

 and vacuum tubes bring them 

 back. The same blower supplies 

 air at about 10 Ib. per sq. in. to a 

 reservoir feeding the various pres- 

 sure tubes, and maintains a vacu- 

 um of 6J Ib. in a vacuum container 

 connected with the return tubes. 

 Pressure in both directions has 

 been adopted for lines with large 

 tubes. The speed of carriers is 

 from 20-30 m. an hour. 



For ordinary purposes circular 

 tubes 2, 2J, and 3 ins. in diameter 

 are used ; but oval and square 

 tubes are employed for special 

 work. The line tubes of the London 

 Post Office are of lead, enclosed in 

 protecting iron pipes. The large 

 6, 8, and 10-in. tubes used in the 

 U.S.A. for mail matter are of cast 

 iron. Curved sections are not 

 given a curvature sharper than 1 

 ft. radius per in. of pipe diameter, 

 and are of seamless brass bored 

 before bending. Carriers are made 

 of brass, vulcanite, or gutta- 

 percha. The body of the car- 

 rier is of smaller diameter than 

 the ends, on .which are fixed 

 felt rings or disks, exactly fitting 

 the tubes. 



Pneumatic Dispatch. 

 Diagram explaining 

 apparatus. See text 



Pneumatics (Gr. pneuma, 

 vapour, breath). Study of the me- 

 chanical properties of gases (q.v. ). 



Pneumatolysis (Gr. pneuma, 

 vapour ; lyein, to set free). In 

 geology, name given to the forma- 

 tion of minerals by the discharge 

 of gases through the original 

 molten mass. Such gaseous dis- 

 charges may be easily seen at the 

 time of any volcanic eruption, and 

 the molten lavas are considerably 

 modified as they cool by the gases 

 which pass through them. 



The chief gases which act on 

 such molten rocks are carbonic 

 acid, hydrogen, nitrogen, fluorine, 

 chlorine, etc., and water vapour, 

 and they have the effect of break- 

 ing up or forming fresh combina- 

 tions of the primary constituents 

 of the molten discharging mass. 

 The gases combine with the metal- 

 liferous minerals in particular and 

 form mineral ores, e.g. copper 

 oxide, ferric chloride, etc. Fluorine 

 acts as a powerful agent, hydro- 

 fluoric acid being formed and, acting 

 on felspars, produces topaz, mus- 

 covite, etc. Pron. New -ma-tolly-sis. 



Pneumogastric OR VAGUS 

 NERVE. Important nerve on each 

 side of the body, which arises from 

 the base of the brain and passes out 

 of the skull through the jugular 

 foramen, an aperture in the base 

 of the cranium. It proceeds verti- 

 cally down the neck, close to the 

 carotid artery, and enters the 

 thorax. The right vagus passes 

 behind the root of the right lung, 

 where it forms the posterior pul- 

 monary plexus. From this the 

 nerve continues down behind the 

 oesophagus and passes through the 

 diaphragm or large horizontal 

 muscle, to supply the posterior 

 surface of the stomach and give 

 off branches to plexuses of nerves 

 in the abdominal cavity. 



The left vagus passes over the 

 arch of the aorta or main blood 

 vessel, and breaks up behind the 

 root of the left lung into the pos- 

 terior pulmonary plexus. The 

 nerve subsequently makes its way 

 down through the diaphragm in 

 front of the oesophagus, and is 

 distributed to the anterior surface 

 of the stomach, with branches to 

 various nerve plexuses. See Anat- 

 omy ; Neck ; Nerve. 



Pneumonia (Gr. pneumdn, 

 lung). Acute infective disease of 

 the lung. The two chief forms are 

 lobar or croupous pneumonia, and 

 lobular or broncho-pneumonia. 



Lobar pneumonia is a wide- 

 spread and fatal disease. Males are 

 more liable to it than females ; it 

 is more common in towns than in 

 rural districts, and poor health, 

 underfeeding, alcoholism, and old 

 age predispose towards the malady. 



Exposure to cold or wet is often 

 the immediate cause, but there is 

 good ground for believing that 

 these factors act only by reducing 

 the powers of the body to resist 

 infection. Pneumonia may also 

 occur in the course of, or as a com- 

 plication of, many other diseases, 

 chiefly phthisis, heart disease, 

 Bright' s disease, diabetes, and 

 acute fevers, as typhoid, diph- 

 theria, influenza, and plague. 

 The Diplococc'us pneumoniae, which 

 was isolated by Fraenkel, is the 

 micro-organism which causes the 

 disease. The first effect of the 

 organism upon the lung is to pro- 

 duce congestion, followed by soli- 

 dification of parts of the lung, pro- 

 ducing the condition known as red 

 hepatisation, which is eventually 

 succeeded by grey hepatisation, 

 after which death, or absorption of 

 the products with recovery, occurs. 

 The symptoms usually begin 

 with a rigor or shivering fit, and 

 rise of temperature to 104 or 105 

 F. Sometimes, however, the onset 

 is insidious. Pain in the side is a 

 frequent symptom, respiration is 

 hurried, and there is a dry cough 

 with tenacious blood-tinged expec- 

 toration. The temperature remains 

 high for from five to nine days, and 

 then falls abruptly, this constitut- 

 ing the crisis of the disease. The 

 patient then usually sweats pro- 

 fusely, the pulse rate drops, the 

 breathing becomes almost normal, 

 and he passes into a state of com- 

 parative comfort. While various 

 complications may arise, and death 

 may occur from collapse, after the 

 crisis, the danger of a fatal ter- 

 mination is now very much less. 

 Complications which may arise are 

 pleurisy, pericarditis, endocarditis, 

 and meningitis. Treatment consists 

 mainly in very careful nursing. 

 The patient should be in the open 

 air, or in a large, well-ventilated 

 room. The diet should be very 

 light, consisting chiefly of milk. 



Broncho-pneumonia is an in- 

 flammation of the small bronchioles 

 or air-tubes of the lung and of the 

 air vesicles. It may occur as a 

 primary infection, or may be 

 secondary to other diseases of the 

 respiratory system, as bronchitis, 

 measles, whooping cough, and in- 

 fluenza. This form of pneumonia 

 is very prevalent among children, 

 particularly those living in towns, 

 who are badly nourished or suffer 

 from rickets, and it is the most 

 common cause of death following 

 measles. The onset in the primary 

 form is usually abrupt, with a 

 sudden rise of temperature and 

 sometimes with convulsions. More 

 frequently the child has suffered 

 for some time from cough and 

 bronchitis. Temperature rises from 



