GLOSSARY 445 



Parachro 'matin (see Chromatin), the achromatic nuclear substance (linin of 



Schwarz) from which the spindle-tibres arise. (Pfitzner, 1883.) 

 Parali'nin (see Linin), the nuclear ground-substance or nuclear sap. (Schwarz, 



1887.) 

 Parami'tome (see Mitome), the ground-substance or interfilar substance of proto- 

 plasm, opposed to mitome. (Flemming, 1892.) 

 Paranu'clein (see Nuclein), the substance of true nucleoli or plasmosomes. 

 Pyrenin of Schwarz. (O. Hertwig, 1878.) Apphed by Kossel to "nucleins " 

 derived from the cytoplasm. These are compounds of albumin and paranucleic 

 acid which yields no xanthin-bodies. 

 Paranucleus (see Nebenkern). 



Par'aplasm (Trapa, beside; -rrXda-fia, something formed), the less active portion of 

 the cell-substance. Originally applied by Kupi^er to the cortical region of the 

 cell (exoplasm). but now often apphed to the ground-substance. (Kupffer, 

 1875.) 

 Periplast (-n-tpL around; TrAao-TOs, form), i. The peripheral part of the cell, 

 including those parts outside the nucleus or "endoplast.'' (Huxley, 1853.) 

 2. A term somewhat vaguely applied to the attraction-sphere. The term 

 daughter-periplast is applied to the centrosome. (Vejdovsky, 1888.) 

 Perisphere (Trept, around), a term applied to the outer region of the attraction- 

 sphere in nerve-cells, and opposed to an inner " centrosphere.'" (Lenhossek, 

 1895.) 

 Plasmocytes (7rAa(r/u,a, Kvro'i), colourless blood-corpuscles supposed to be free 



attraction-spheres. (Eisen, 1897.) 

 Plasmosphere, the same as Perisphere. 



Plas'mosome {irXdafjia, something formed (i.e. protoplasmic) ; awfjia, body), the 

 true nucleus, distinguished by its affinity for acid tar-colours and other " plasma- 

 stains."" (Ogata, 1883.) 

 Pla'some (-rrXdaixa, a thing formed; awfm, body), the ultimate supra-molecular 



vital unit. See Biophore, Pangen. (Wiesner, 1890.) 

 Plas'tid (TrAasTos, form), i. A cell, whether nucleated or non-nucleated. (Hackel, 

 1866.) 2. A general term applied to permanent cell-organs (chloroplasts, etc.) 

 other than the nucleus and centrosome. (Schimper, 1883.) 

 Plas'tidule, the ultimate supra-molecular vital unit. (Elssberg, 1874; Hackel, 



1876.) 

 Plas'tin. a term of vague meaning applied to a substance related to the nucleo- 

 proteids and nucleo-albumins constituting the linin-network (Zacharias) and the 

 cytoreticulum (Carnoy). (Reinke and Rodewald, 1881.) 

 Pluri'valent (p/us, more; valere. to be worth), applied to chromatin-rods that 



have the value of more than one chromosome sensu strictu. (Hacker, 1892.) 

 Polar bodies (Polar globules), two minute cells segmented off from the ovum 

 before union of the germ-nuclei. (Disc, by Carus, 1824; so named by Robin, 

 1862.) 

 Polar corpuscle, the centrosome. (Van Beneden. 1876.) 



Polar rays (Polradien), a term sometimes applied to all of the astral rays as 

 opposed to the spindle-fibres, sometimes to the group of astral rays opposite to 

 the spindle-fibres. 

 Pole-plates (End-plates), the achromatic spheres or masses at the poles of the 

 spindle in the mitosis of Protozoa, probably representing the attraction-spheres. 

 (R. Hertwig, 1877.) 

 Polyspermy, the entrance into the ovum of more than one spermatozoon. 

 [Prochro'matin] (see Chromatin), the substance of true nucleoli, or plasmosomes. 

 Equivalent to paranuclein of O. Hertwig. (Pfitzner, 1883.) 



