PNEUMONIA. 142 PO. all.r. Death takes place in fatal cases from heart failure, due to toxemia. Durin;; the prog- ress of pneumonia, the airected portion of the lung goes through three stages. In the first or stage of hviier.xmia. the lung is congested, lias a reddish hrown color, and there is a slight exuda- tion into the air cells. It is heavier than normal and contains less air. This sUigc lasts from one to three days, and is followed by the stage of exudation or red hepatization. In this the lung is red ( resemhling, when cut into, a section of liver), sinks in water, and the air sacs are com- pletely iilled with viscid, fibrinous lluid mixed with blood corijuseles. In from three to seven days the stage of resolution or gray liepatization set's in. The exudate filling the alveoli now un- dergoes licjuefaction and is partly absorbed and partly expelled by acts of expectoration. This stage" may endure from one to three weeks. Some- times resolution is delayed, the exuded material undergoes purulent transformation, and single or muUi|ile abscesses of the lung result. Pneumonia is a self-limited disease, and treatment is there- fore not directed toward cutting short an attack, hut toward keeping up the patient's strength, supporting the heart, and reducing the tempera- ture. It is particularly in the second stage that the patient is in danger, when the fever is at its height and the lieart embarrassed. Alcohol, strychnine, and strophantlius are the most useful cardiac stimulants, and cold sponging and cold packs or baths the usual methods of reducing the fever. During the third staf;c expectorants are exhibited to assist in bringing uj) the exudate, and during convalesc<'nce tonics are given to build up the strength and restore the wasted tissues. Uroncho-pneumonia (catarrhal or lobular pneu- monia) attacks princi])ally young children and old people by an extension downward of a bron- chitis. It often occurs as a complication of the eruptive fevers, especially measles, and of whoop- ing-cough. The disease affects the mucous mem- brane lining the finer bronchial tubes (whence it has been called capillary luonchitis) and the air cells. These become blocked up by a yellow- ish mucoid material and larger or smaller por- tions of the lung are deprived of air. The symp- toms of this variety of pneumonia are similar to those of the croupous form, except that the tem- perature rises more gradually and the rapidity of respiration is out of all projiortion to the amount of tissue involved. The disease may be acute, subacute, or chronic in its course, and nearly one-half of the cases die. The treatment is designed, as in croupous pneumonia, to keep up the strength, and assist in the expectoration of the toxic material. A steam kettle is kej)t going in the sick-room, poultices are applied to the chest, and expectorants and a nourishing liquid diet are given throughout the attack. Chronic interstitial pneumonia (cirrhosis of the lung) is a comparatively rare disease, found in miners, stone-cutters, grinders, and others whose occupation necessitates the inhalation of irri- tating ])artieles. It sometimes follows acute pneumonia in which resolution has been delayed, and generally terminates as a tuberculous pro- cess. There is an overgrowth of the fibrous framework of the lung at the expense of the re- spiratory elements. The organ shrinks some- times to half its normal size, and is heavy and tough in consistence. There is always an asso- ciated chronic bronchitis, with cough and ex- pectoration. The course of the disease is .slow, exteniiing over ten or fifteen years. The treat- ment of this disease consists in placing the pa- tient under the licst jiossilile hygienic and cli- matic conditions — a warm climate in tlic winter , and a bracing one in the summer, with the ad-j ministration of tonics, such as codliver oil, iron,' and (luinine. Among animals the horse perhaps most fre- quently exhibits symptoms characteristic ofj pneumonia. Had ventilation, improjier attention! to the needs of the animal, etc., are frequent! catises. Remedies are similar to tho.se used fori the human subject. PNOMPENH (/■'(•. pron. pnON'pen'). The capital of the French jirotectorate of Cambodia, K)0 miles northwest of Saigon, on the ilekong Kivcr (Map: Frencli Indo-Cliina, K ."j). The most noteworthy features are the palace of the lUul- dliist priests, the Government buildings, and the ])agoda. The shelling of cotton seeds is an ini- |)cirtant industry, and the town is also a promi- nent trade centre. Population, a1)out 50,000. PNYX, niks (Lat., from Gk. nuif). A hill and ancient place of assembly, whose exact loca- tion is not known, in Athens. PO (anciently I'ndus and EriJjinux). The J largest river of Italy, (lowing through Piedmont] and Lombardy. and along the southern borders" of Venetia. It rises on jlonte Viso, in the Cot- tian Alps, and fiows in a general easterly direc- tion through the great valley between the Alps and the Apennines, emptying into the Adriatic Sea after a course of .lilO miles (Map: Italy, F : y). It falls verj' rapidly in its extreme ujiper , course, its ultimate sources being at a height of | 0000 feet. In the lower half of its course, hovv- ever, it is a comparativelv sluggish stream, (low- ing over a raised alluvial bed so that its surface ' is higher than the surroimding country, and its banks have to be protected liy dikes, which extend continuously from Cremona to the delta. These levees, however, do not follow the smaller wind- ings of the river, but cut across peninsulas, which, though unprotected, are cultivated, but are submerged at every considerable rise of the river. The volume of water discharged by the river is nearly cipial to that of the Rhine. The greater part is received from the Alps, and nearly one- half comes from the series of large lakes on the southern slojie of the mountains. The principal tributaries from the left are the Dora Riparia, Dora Haltea, Sesia, the Ticino, the outlet of Lago Maggiore, the Adda from Lago di Como, the Oglio from Lago d'lseo. and the Wincio from Lago di Garda; from the right the Po receives the Tanaro, Trebljia, Taro, and Panaro. Since the Po is fed exclusively by mountain torrents, the quantity of sediment carried by its current is enormous, the absolute quantity being nearly equal to that car- ried by the Mississippi. As a result of this the delta of the Po grows with nearly the same ra- pidity as that of the great American river: it advances into the Adriatic at the rate of more than 200 feet per year. The delta and the sur- rounding country consist of unlicalthful marslies, and there are scarcely any towns on the lower course of the river. The chief cities on its banks are (ascending) Cremona. Piaccnza. Casale Monferrato (the head of navigation. 337 miles from the mouth), and Turin. The plain of the Po is of great fertility.
