_Celosia_, 250. _Centaurea_, 188. _Centhorhynchus_, 219. _Cephaleuros_, 188. _Cephus_, 248. _Cercis_, 259. _Cercospora_, 190. Cereals, 248. Change of conditions, 78. Charlock, 165. Checks to disease, 166. Chemical analysis, 32, 64, 103, 272. Chemical antiseptics, 159. Chemical energy, 29, 287. Chemotactic phenomena, 72, 130, 135, 137. _Chermes_, 153, 223. Cherry, 208, 209, 231, 234, 235, 247, 248. Chestnut, 190. Chlorine, 181. Chlorophyll, 19, 106, 122. Chlorophyll action, 184, 192. Chlorophyll corpuscles, 9, 18, 22. Chlorosis, 122, 165, 179, 180, 181. Chrysanthemum, 243, 252. Chytridiaceae, 127, 136, 189, 208. _Cicada_, 235. Cicatrix, 123. _Cinchona_, 168, 172, 173. Circulation of carbon, 62. Circulation of nitrogen, 62. _Citrus_, 168. _Clasterosporium_, 188, 209. Classification of diseases, 99, 101, 120. _Claviceps_, 232. Climate, 1. Climbing plants, 112, 113, 210. _Clostridium_, 236, 237. Clothes, 142. Clover, 164, 187, 249, 252, 288. Cluster-cups, 188. Coal gas, 104, 182. Coccideae, 164, 232. _Coccus_, 223. Coffee leaf-disease, 114, 146, 166, 169, 242. _Coleophora_, 153, 206. _Coleosporium_, 169. _Coleus_, 192, 220. Competition of fungi, 61. Complex interactions, 91, 99. Conifers, 125, 205, 223, 225, 234, 258. Constitution, 156, 283. Consumption, 248. Contact irritability, 125, 135. _Contagium fluidum vivum_, 183. Contortions, 252. _Convallaria_, 175. _Convolvulus_, 112. _Copaifera_, 234. Copper sulphate, 162, 165. Coppery leaves, 191. Cork, 119, 123, 194, 199, 216, 222. Cork wings, 217. Corky warts, 212. Corn, 248. Corrosion of marble, 46. _Cossus_, 206. Cost of epidemics, 146, 147. Cotton, 172. _Crassula_, 253. Creeping of mycelia, 142. _Crepis_, 252. Crimson spots, 189. Cross-breeding, 266. Cross-fertilisation, 69, 74, 77, 281. Cross-graining, 124. Crucifers, 219, 284. Cryptogams, 87, 108, 111, 113. Cuckoo-spit, 233. Cucullate leaves, 253. Cucumber, 219. _Cucurbitaria_, 217, 243. Cultivation of pest and host plant, 168. _Curculio_, 248. Curling, 235, 246. _Cuscuta_, 134. Cuts, 119, 143, 194. Cuttings, 194, 198, 262, 263. Cyanide of potassium, 165. Cycads, 128. _Cynips_, 110, 213, 219. _Cystopus_, 116, 136, 175, 187, 217, 247, 252. Cytases, 132. _Cytisus Adami_, 264, 283. Daisy, 278. Damping off, 114, 144, 160, 229, 284. Dandelion, 247, 252. Daniel's researches, 283. Dark heat rays, 27. Darwin, 72, 125. _Dasyscypha Willkommii_, 152, 223. Death, 271, 272, 287, 290. De Bary, 85, 151. Deficiency of iron, 180. Defoliation, 109, 240, 244. Deformation, 132. _Dematium_, 135. _Dematophora_, 143, 145. Denitrification, 62. Derivation of Phytopathology, 85. Destruction, 275. Development of root-hairs, 40.