478 



Index and Glossary 



forcing effect of, 263; tor loam and 

 clay soils, 253; functions of, on 

 light soils, 254; legumes suitable 

 for heavy soils, 259; leguminous, 

 value of, origin of, 239; nitrogen 

 content of, 245; on sandy soils, 241, 

 243; relation to soil-humus, 237; 

 smaller returns from on heavy soils, 

 259; value of, for soil-improvement 

 242. 



Grotenfelt, 362, 367, 408. 



Gypsum (sulfate of lime) , 295, 297, 34S . 



Hall, 312. 



Haubner, 342. 



Hauser, 465. 



Hay, bacteria in, 451; brown, bac- 

 teriological activities in, 453; freshly 

 cut, rise of temperature in, 451; 

 heating of, 452, 453; preparation of, 

 451; relation of bacteria to, 452. 



Health and disease, relation of water 

 to, 56. 



Hellriegel, 195, 210, 212, 213, 221. 



Hemp, bacteria in the preparation of, 

 456. 



Hennebeig, 307, 465, 466, 469. 



Herring brin^, bacteria in, 441. 



Henle, 6. 



Higgs, 106. 



Hilgard, 279. 



Hiltner, 227, 229. 268, 272. 



Hippocrates, 57. 



Hippuric acid (a nitrogenous sub- 

 stance found in considerable pro- 

 portion in the urine of herbivorous 

 animals), 321. 



Hoffmann, 5. 



Hospitals, bacteria in the air of, 53. 



Humic acids (sour substances found in 

 humus), 151. 



Humus, decomposition of by bacteria, 

 146; disappearance of carbon from, 

 154; exhaustion of in cultivated 

 soils, 152; formation of iri moor and 

 heath soils, 152; in sandy soils, 153; 

 nitrogen compounds in, 156; phos- 



phoric acid in, 283, 284; proportion 

 of in acid soils, 145; rate of decay of, 

 149; raw, 145; relation of crop-ro- 

 tations to, 239, — bacteria to, 144, 

 — green-manuring to, 238, — 

 potash to, 291, — to water-holding 

 power of soil, 144. 

 Hydrolysis (chemical change prom- 

 inent among others in the decom- 

 position of proteids by bacteria, 118. 



Ice, bacteria in, 97, 98. 



Ice, use of, in the transportation of 

 milk, 395. 



Immunity (ability to resist infection), 

 11. 



Impermeable, 29. 



Inoculation (the introduction of 

 definite species of bacteria, or other 

 microorganisms, into animals, 

 plants, or any media presumably 

 suitable for their development), on 

 various soils, 224; soil, cotton cul- 

 tures, 233, 234, — history of, in 

 U. S., 230, — liquid cultures, 234, — 

 Moore's method, 232, — with alinit, 

 235, — with pure cultures, 226, — 

 method of securing, 226; soil 222, — 

 defects of, 225, — diseases intro- 

 duced by, 225, — lessons taught by, 

 225. 



Intermittent filtration (that is, not 

 continuous filtration), 116. 



Intermittent sterilization, 24. 



Involution forms (bacterial cells of 

 irregular or abnormal shape, and 

 size, usually due to unfavorable 

 conditions of growth), 15. 



Iron bacteria, 301; as geological 

 agents, 302; importance of, 301; 

 influence of, on azotobacter, 302; 

 potential energy in, 300; produc- 

 tion of nitrates by, 195; relation of 

 bacteria to, 299, 300; relation of 

 decay bacteria to, 302; rust, 300; 

 soluble compounds of, 301 ; sul- 

 fate of, 299. 



