348 Life and Health 



Pep'tone (Gr. TT^TTTCIJ', to cook). A proteid body formed by the action of 

 ferments on albumins or other proteids during gastric and pancreatic 

 digestion. 



Per / i-car / di-um (Gr. ire/>, about, and Kapdla, heart). The sac enclosing the 

 heart. 



Pert-os'te-um (Gr. ircpL, around, and do-rtov, a bone). A delicate membrane, 

 which invests and nourishes the bones. 



Pert-startle move'ments, or peristalsis (Gr. irepl, round, and a-i-AXeii;, to 

 send). The slow, wave-like movements of the stomach and intestines. 



Pert-to-ne'um (Gr. irepirriveiv, to stretch around). The investing mem- 

 brane of the stomach, intestines, and other abdominal organs. 



Pha-lan'ges (Gr. <j>d\ay, a body of soldiers closely arranged in ranks and 

 files). The bones of the fingers and toes. 



Pharynx (Gr. 4>dpvy, the throat). The cavity behind the mouth and the 

 nose, leading to the gullet. 



Pi'a ma'ter (Lat.). Literally, "the tender mother"; the innermost of the 

 three coverings of the brain. It is thin and delicate; hence the name. 



Pin'na (Lat., a feather or wing). External cartilaginous flap of the ear. 



Plas'ma (Gr. TrXatro-etv, to mould). The fluid part of the blood and 

 the lymph. 



Pleu'ra (Gr. TrXevpd, the side, also a rib). A membrane covering the lung 

 and lining the chest. 



Plex'us (Lat. plectere, to braid). A network of vessels, nerves, or fibers. 



Pneu'mo-gas'tric (Gr. irve^uv, the lungs, and yaffrrfp, the stomach). The 

 longest of the cranial nerves giving off branches to the lungs, the heart, 

 the alimentary canal, and other parts ; also called the vagus, or wander- 

 ing nerve. 



Poi'son (Fr., from Lat. potio, a draught). A substance that when introduced 

 into the body either destroys life or impairs seriously the function of 

 one or more of its organs. 



Pons Va-roli-i (Lat. pans, a bridge, and Varolius). The white fibers which 

 form a bridge connecting the different parts of the brain, first described 

 by Varolius. 



Pop-li-te'al (Lat. poples, poplitis, the ham, the back part of the knee). The 

 space behind the knee joint is called the popliteal space. 



Portal vein (Lat. porta, a gate). The venous trunk formed by the veins 

 coming from the stomach and the intestines. It carries the blood 

 to the liver. 



Pres'by-o'pi-a (Gr. irptrpvs, old, and oty, the eye). A defect of the accom- 

 modation of the eye, caused by the hardening of the crystalline lens; 

 the farsightedness of adults and aged persons. 



