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GLOSSARY OF IMPORTANT TERMS 



the blood which helps colorless 

 corpuscles destroy bacteria. 



Organ : each part in an animal or 

 plant which performs some special 

 work. 



Organic : pertaining to living things. 



Organism : a body which is made up 

 of organs or parts, each oi which 

 has a special function ; any animal 

 or plant. 



Osculum os'kii Him) : the large open- 

 ing at the end of a sponge. 



Osmosis os ino'sis) : diffusion of 

 water through a semi-permeable 

 membrane, the greater flow being 

 toward the lesser concentration of 

 water. 



Ovary o'vd rl : in a plant, the base 

 of a pistil, containing the ovules; 

 in an animal, the egg-forming gland. 



Ovipositor o'vi poz'i ter) : a special- 

 ized structure for depositing eggs, 

 foimd in insects. 



Ovule o'vuT : a rounded structure 

 in the ovary, which may become a 

 seed. 



Oxidation ok'si da'shfm) : the chemi- 

 cal union c 

 substance. 



Oxygen (ok'si jfeO : a gaseous element 

 found in the air and in many com- 

 pounds. 



Oxyhemoglobin i ok'si he'mo glo'bin) : 

 a combination of oxygen with 

 haemoglobin. 



Palate (paTat) : the roof of the mouth. 

 The hard palate is supported by 

 bone ; the soft palate is a fold of 

 mucous membrane lying posterior 

 to the hard palate. 



Palisade layer : a layer of green cells 

 under the upper epidermis of a leaf. 



Palpus (pal'pus) or palp : in arthro- 

 pods, an appendage attached to a 

 mouth part ; usually an organ of 

 touch or taste. 



Pancreas rpan'kre as) : a digestive 

 gland. It secretes pancreatic juice. 



Pappus (pap'fts) : a downy or fluffy 

 out growth from the ovary wall. 



Parasite par'ri sit ) : an organism 

 which secures its living directly 

 from another living organism with- 

 out giving anything in return. 



Parathyroids : the four small endo- 

 crine glands attached to the thyroid 

 glands. 



Pasteurize -pas'ter iz ) .from Pasteur 

 the scientist : to heat milk to about 

 140° Fahrenheit for about 30 min- 

 utes for the purpose of killing bac- 

 teria in it. 



Pathogenic (path'o jen'ik ) organisms : 

 bacteria or protozoa which cause 

 disease. 



Pectoral girdle : bones which support 

 the anterior pair of appendages in 

 vertebrates. 



Pelvic girdle : the bony arch to which 

 the posterior pair of appendages are 

 attached in vertebrates. 



Pepsin : the enzyme, in the gastric 

 juice, which begins the digestion of 

 proteins. 



Peptones ipep'tonz , > : substance pro- 

 duced by the action of pepsin on 

 proteins. 



Perennial per en'i cfl) : lasting or con- 

 tinuing more than two years. 



Perfect flowers : flowers with both 

 stamens and pistils. 



Peristaltic per'I sTal'tik : wavelike 

 movements of the muscles of the 

 food tube. 



Petal : one of the leaflike parts of the 

 corolla. 



Petiole (petfi ol) : the stalk of a leaf. 



Phagocyte fag'o sit : a colorless cor- 

 puscle which destroys bacteria. 



Pharynx far'inks"' : the part of the 

 alimentary canal between the mouth 

 and the esophagus. 



Phloem (flo'em) : that part of the 

 fibrovascular bundle which contains 

 the sieve tubes. 



Photosynthesis (fo'to sin'the sis" : the 

 process of making starch out of 

 carbon dioxide and water by the 

 aid of sunlight, as is done bv a green 

 ceU. 



Phototropism (fo'tot'ro piz'm) : reac- 

 tion to light. 



Phylum fi'lfmi) : a large division of 

 the plant or the animal kingdom. 

 It is composed of classes. 



Physiological fiz'i oloj'I kdi) division 

 of labor : performance of different 

 kinds of work by different parts of 

 an organism. 





