PUZZUOLANA. 568 PYAT. much used in Holland in fresh water and marine engineering work. Similar volcanie ash is found invntral France. Artilicial puzzuolanas may be made from slag, brick dust, or ashes. The use of puzzuolaua as a hydraulic agent was known to the ancients. Consult: Heath, A Manual of Lime and Cement (London, 1893): Schocli, Die moderne Aiifbercitiwg und Wertung dcr MiirtcU ilaterialien (Berlin, 1890). See Cement. PY.3;MIA (XeoLat., from Gk. vOov, pi/oii, pus + af/ia, haima, blood). This term and that used to designate the closely allied condition, se])tic;emia, originated liefore the idea of bac- teria as the etiological factor in the diseases was developed. They have become so fixed in medical nomenclature, however, that they are still re- tained. Before the discovery of bacteria as the e.citing cause, it was the general belief that septicaMiiia was a condition caused by the pres- ence in the I)lood of sul)stances undergoing putre- faction, while i)yicmia was due to the presence of pus itself in blood channels. In the light of our present l)acteriologieal knowledge, we recognize septicicniia as a condition in whiih both bacteria and their toxins arc scattered throughout the body by means of the vascular and lymph sys- tems; while pya-mia represents a form of septi- caemia in which, in addition to the general distri- bution of septic material throughout the body, this material containing bacteria becomes lodged at dill'erent points, thus setting up local foci of in- fection known as metastatic abscesses. These new abscesses usually occur along lines of easiest blood and lymph comnuinication with the point or points ])rcvinusly infected. Tluis in suppuration of the intestines the most common seat of me- tastatis is the liver, while from septic foci in bones, nuiselcs, skin, etc., abscesses may develop in lungs, kidnej', spleen, and other organs. After death from pyiemia there may be no visible changes, even the localized foci of infectioii being too small to be seen by the miked eye. The wound from which the infection originated may look in- flamed or gangrenous. Extensive thrombi in the near-by veins are not uncommon. Thrombosis may also occur in veins at a dis- tance from the wound. In infections following amjiutation of the leg it is not uneoiiiiiion to find the femoral vein hlled with a purulent mass as high up as Poii|)art's ligament. As a result of the thrombosi.s, infarction or death of tissue from interference with its nutrition occurs. Metastatic abscesses may be found in the lungs, kidneys, liver, intestines; in fact, in any of the viscera. Those in the lungs are chiefly near the pleural surfaces and in the lower lobes. Serous ell'usion, often with much fibrin, may occur into the pleural and pericardial cavities. Local inlhitumation of joints, cspeeially of the knee and shoulder, may occur. 'ith the excep- tion of those occurring in serous membranes, these inflammations are usually purulent in character and of the same general nature as the metastatic abscesses. Microsco|)ical examination frequently shows congestion of the viscera, with acute degeneration of the parenchyma cells of the kidney, liver, spleen, etc. Chromatolysis of the cells of the brain and spinal cord oeeurs, also swelling of the lymph nodes with prolifera- tion of their elements. An increase in the num- ber of white blood cells is of almost constant occurrence. While other species of bacteria act as occasional excitants of pya-mia and septi- ca-niia, two species are so frequently associated w'ith this condition that they have received the name of the |)Vogenic cocci. They are known as the staphylococcus and the streptococcus. The .staphylococcus pyogenes aureus is the micro- organism most frequently associated with suppvir- ation. It is a small round coccus averaging about one micron in diameter. It grows in groups somewhat resembling bunches of grapes, from which characteristic its name is derived. It is non-motile. It grows well on the ordinary cul- ture media, such as beef broth, agar, gelatin, milk, and potato, at room temperature. On some of the media it develops a rich golden color, whence its name of aureus. It stains easily with aniline dyes, and does not decolorize with Gram's metliod. The staphylococcus pyogenes albus. .so called from the whiteness of its colonies, is a less frequent and less violent inciter of suppuration than the staphylococcus pyogenes aureus, it may occur in association with the latter or alone. The staphylococcus epidermis albus is a rather weak pj'ogenic coccus .sometimes found in stitch abscesses. The streptococcus pyogenes is also a common cau.se of supt)uration and may occur either alone or in association with the staphylococci. Its effects are quite similar to those of the staphv- lococci. Upon culture media it grows somewhat more slowly than the stai)liylococci and differs from the latter in not fluidifying gelatin. Its colonies are ai)t to be of a grayish color. It is non-motile, an<l when seen under the microscope shows its tendency to form chains, whence its name. While the aljove are the most common ex- citants of suppuration, other microorganisms may act as causative factors. Thus the typhoid bacillus has been found in pure culture in acute suppurative inflammations of the middle ear. in osteomyelitis, in empya'iua, and in localized peri- tonitis occurring during or after an attack of typhoid fever. The pneumococcus has been found alone in abscesses of the soft parts, in purulent cerebro-s|)inal meningitis, synovitis, pericarditis, and suppurative iiiflanunation of the middle ear. The bacillus coli comnumis has been found in pure culture in abscess of the liver, in apjien- dieitis, in acute peritonitis, in purulent inllani- mation of the gall bladder, and in other inflam- matory conditions. Among the less commipii ex- citants of su|)puration may be mentioned the gonococcus, the micrococcus tetragcnus. the bacillus pyocyanus, the bacillus of glanders, the diplococcus of cerebrospinal meningitis, and the bacillus pyogenes f<etidus. PYAT, pya, Ffiijx (1810-89). A French Communist and journalist. He was born at Vierzon, and trained for the law. After the failure of the Socialist call to arms in 1849, he escaped to Switzerland. Thence he went to Belgium and England as a member of the Euro- pean Revolutionary Committee. The events or 1870 brought him back to France to take active part in the Commune. He was a prime mover in the overturning of the VendOme Column, and on the collapse of the Commune escai)ed to Lon- ilon. In his absence he was condemned to death (187.3), but he was pardoned (1880) and elected neputv from Marseilles (1888). I'yat died at Saint (Jratien, August 4, 1889. He contributed to many newspapers and edited several revolu- tionary journals. He wrote several very popular
