678 



Journal of Agricultural Research 



Pinus — Continued. Page 



taeda, germination in mineral soil 526 



virginiana — 



germination in mineral soil 526 



host of Peridermium cerebrum 625 



Pipette holder for distribution of serum . . . 613-618 

 Pitch pine. See Pinus rigida. 

 Pittman, D. W., and Harris, F. S. (paper): 

 Soil Factors Affecting the Toxity of 



Alkali 287-319 



Plant bug — 

 four-lined. See Poecilocapsus lineatus. 

 meadow. See Miris dolabralus. 

 tarnished. See Lygus Pratensis. 



Plants, hardening against frost 8j-iii 



Plasmolysis of cells — 



caused by freezing 90-93 



effect on hydrogen-ion concentration of sap . 99 

 Plasticity of Biologic Forms of Puccinia 



graminis (paper) 221-249 



Plenodomus destruens, causal organism of foot- 

 rot of Ipomoea batatas 350 



Plot tests, field technic 231-262 



Plowsole, relation of inorganic soil colloids 



to 505-519 



Poa pratensis — 

 catalase and oxidase content of seeds .... 137-174 



food plant of Miris dolabratus 183 



Poecilocapsus lineatus, pest of currants i8i 



Polypeptids in normal and blighted spin- 

 ach 385-404 



Polyphagus euglenae, similarity to Cronartium 



ribicola 648 



Polysaccharids in hardened and nonhardened 



cabbage 95-96 



Pomegranate melon. See Cucumis melo var. 



dudaim. 

 Popillia japontca, larvae, effect of hydrocy- 

 anic-acid gas on 134-136 



Populus — 

 alba, attacked by Melampsora pinitorqua . . 551 

 balsamifera candicans, attached by Mel- 

 ampsora pinitorqua 531 



tremula, attached by Melampsora pinitor- 



gua 551 



Porthetria dispar, used in experiments with 



Limnerium validum 458 



Potash in — 



greensand 483-493 



Hagerstovni silty loam, soluble in — 



ammonium-chlorid solution 67-70 



carbonated water 67 



distilled water 64-66 



hydrochloric acid 63-64 



Potassium — 

 chlorid, used in experiments with green- 

 sand 488 



cyanid, tolerance of larvae of Trickinella 



spiralis to 477-479 



in greensand 483-492 



nitrate, used in experiments with green- 

 sand 488-492 



oxid in — 



normal and blighted spinach 371-375 



greensand 485 



phosphate in solution used in experiments 

 with greensand 486-492 



Page 

 Potassium-alum solution, used in determining 



protein nitrogen in spinach 391-393 



Potassium-nitrate method, used in deter- 

 mining soil acidity 322-329 



Potato- 

 sweet. See Ipomoea batatas. 

 See Solanum tuberosum. 

 Potentiometric determination of changes in 

 hydrogen-ion concentration of plant sap 



during freezing 99-101 



Protein — 

 digestibility in alfalfa hay and starch. . . . 271,287 



in dry matter of feeding stuffs s7o 



in hardened and nonhardened cabbage. 97,103-104 



in normal and blighted spinach 385-404 



Pseudomonas — 

 cilri — 



susceptibility of rutaceous plants 661-666 



virulence to Rutaceae 661-666 



lachrymans. Syn. Bacterium lachrymans. 

 Puccinia — 



dispersa, plasticity of biologic forms 221 



falcariae, asciospore chains 647 



graminis — 



plasticity of biologic forms 221-249 



agrostis, plasticity of biologic forms .... 241-247 

 avenae, used in bridging-host experi- 

 ments 227-249 



phleipratensis, plasticity of biologic 



forms 241-247 



secalis. used in bridging-host experi- 

 ments 22s 



trilici, used in bridging-host experi- 

 ments 225-249 



tritici-compacti, used in bridging-host 



experiments 227-249 



Pucciniastrum agrimoniae, structure of ure- 



dinium 632 



Pulverization of seeds, effect on catalase ac- 

 tivity 143-145 



Pumpkin. See Cucurbita pepo. 

 Pyrocatechin, used as test for oxidasein frozen 



cabbage leaves 88 



Pyrocatechol, used to determine oxidase ac- 

 tivity of — 



normal and blighted spinach 377-380 



seeds 162, 166 



Pyrogallol, used to determine oxidase in — 



frozen cabbage leaves 88 



normal and blighted spinach 377-380 



seeds 162, 166 



Pseudotsuga tazi folia, host of damping-off para- 

 sites 531-558 



Pythium debaryanum., cause of damping-off in 



conifers 523-558 



Rabbit, weight of heart 411 



" Rain-barley," relation to after-ripening 153 



Rambler roses, resistant to brown canker. . 593-600 

 Reagents used in determining oxidase activ- 

 ity of seeds 162, 166 



Red clover. See Trifolium pratense. 



Red manganese oxid in normal and blighted 



spinach 371-375 



Red pine. See Pinus resinosa. 

 Reducing sugars in — 



hardened and nonhardened cabbage 95-96 



healthy and blighted spinach 381-384 



Reduviolusferus, natural enemy of Miris dola- 

 bratus 194. 196 



