xviii LIST OF ILLUSTRATIONS 



FIG. PAGE 



146. Pear scab 246 



147. Toadstool fungus on cherry trees 247 



148. Effect of beet blight . 248 



149. Club foot of turnip . . .249 



150. Tumbler containing a slice of potato covered with cotton . 250 



151. Two bottles containing () bacteria which need air to 



grow, (b) bacteria which cannot grow when air is present 251 



152. A pail for sterilizing 252 



153. Flat bottle containing gelatin used for counting bacteria . 252 



154. Map showing the cholera cases in the great epidemic in 



Hamburg in 1892 259 



155. Bottle containing sterilized gelatin over which a fly was 



allowed to walk 263 



156. Various forms of the cabbage plant, all drawn on the same 



scale 268 



157. Various forms of the cabbage plant, all drawn on the same 



scale as in Figure 156 269 



158. Combined harvester ........ 274 



159. Threshing grain ......... 276 



160. Hay making in tfye old-fashioned way ..... 282 



161. Stacking alfalfa hay in Idaho ...... 286 



162. Growing sugar-beet seed in Utah . 293 



163. Hop field 296 



164. Fruit orchard in the plains country, Utah .... 300 



165. Prune orchard in blossom .''. 301 



166. Packing apples, Oregon 303 



167. Drying prunes .-..?, 305 



168. Orange orchard . 307 



169. Picking olives . . . . . . . . .308 



170. Vineyard ........... $10 



171. Giant grapevine at Carpenteria, California . . . .311 



172. Tokay grapes .313 



173. Lettuce farm ......... 319 



173 a. Strawberry field .327 



174. The melting snows keep the forests green, and they in turn 



hold back the water 335 



175. The result of cutting down the forests .... 336 



