GLOSSARY. 



133 



certain times in the year describe 

 a circle during the day. 



Periscope (Gr. -rrepi, per'i, about ; 

 (T/coTreco, skop'eo, I look). A gene- 

 ral view. 



Perlsperm (Gr. irept, per'i, about ; 

 a"7rep/j.a, sperma, seed). The albu- 

 men or nourishing matter stored up 

 with the embryo in a seed. 



Peris'sodactyle (Gr. 7rept<r<ros, peris'- 

 sos, odd, or uneven ; SaKrvXos, 

 datttulos, a finger). Having an 

 uneven number of toes on the hind 

 feet. 



Peristal'tic (Gr. nepi, per'i, about; 

 tpreAAcu, stello, I send). Sending 

 round : applied to a motion like 

 that of a worm, such as takes place 

 in the intestines and other internal 

 muscular organs, by the contrac- 

 tion of successive portions. 



Perlstome (Gr. irepi, per'i, around ; 

 ffrofMa, stom'a, a mouth). The 

 ring of bristles situated close round 

 the orifice of the seed-vessel in 

 mosses. 



Peristyle (Gr. irepi, per'i, around; 

 CTTV\OS, stulos, a pillar). A range 

 of columns surrounding any thing. 



Perit'omous (Gr. wept, per'i, around; 

 Tf/jLvca, temno, I cut). In miner- 

 alogy, cleaving in more directions 

 than one parallel to the axis, the 

 faces being all of one quality. 



Peritone'al (Peritone'um'). Belong- 

 ing to the peritoneum. 



Peritone'um (Gr. irepi, per'i, about ; 

 Tfivu), teino, I stretch). The se- 

 rous membrane which lines the 

 cavity of the abdomen, and is re- 

 flected over the organs contained 

 therein, so as to hold them in their 

 place, and at the same time allo\v 

 free movement where required. 



Peritoni'tis (Peritone'um; it-is, de- 

 noting inflammation). Inflamma- 

 tion of the peritoneum. 



Peritre'ma (Gr. irepi, per'-i, around ; 

 TptifjLa, trema, a hole). The raised 

 margin which surrounds the breath- 

 ing holes of scorpions. 



Per'meable (Lat. per, through ; meo, 

 I pass). Capable of being passed 

 through without rupture or appa- 

 rent displacement of parts. 



Per'meate (Lat. per, through ; meo, 

 I pass). To pass through without 

 rupture or apparent displacement, 

 as water through porous stones, or 

 light through transparent bodies. 



Permuta'tion (Lat. per, through ; 

 muto, I change). An exchange ; 

 the different combination of any 

 number of quantities, taking a cer- 

 tain number at a time, with refer- 

 ence to their order. 



Perone'al (Gr. irepov-r), per'one, the 

 fibula, or small bone of the leg). 

 Belonging to, or lying near the 

 fibula. 



Peroxide (Lat. per, very ; oxide). 

 The oxide of a substance which 

 contains most oxygen, but has not 

 acid characters. 



Perpendic'ular (Lat. perpendic'ulum, 

 a plumb-line). Hanging in a 

 straight line towards the centre of 

 the earth or of gravity ; meeting 

 another line at right angles. 



Persis'tent (Lat. persis'to, I con- 

 tinue). In botany, applied to parts 

 which remain attached to the axis. 



Per'sonate (Lat. perso'na, a mask). 

 In botany, applied to an irregular 

 corolla with the petals inverted, 

 and having the lower lip projecting 

 so as to close the opening between 

 the lips. 



Perspec'tive (Lai.per, through; spec'- 

 to, I look). The science which 

 teaches the representation of an 

 object or objects on a surface, so 

 as to affect the eye in the same 

 manner as the objects themselves. 



Perspira'tion (Lat. per, through ; 

 spi'ro, I breathe). The exhalation 

 of vapour or fluid through the 

 skin. 



PersuTphate (Lat. per, very ; Bul- 

 phate). A combination of sul- 

 phuric acid with a peroxide. 



Perturba'tion (Lat. per; turbo, I 

 disturb). A disturbing ; in astro- 

 nomy, applied to the deviation, 

 produced by the gravitation of a 

 body external to the orbit, of a 

 planet or other revolving body, 

 from the path which it would follow 

 if regulated solely by the attraction 

 of a central body. 



