176 Mississippi Valley Horticultural Society. 



Now, only the trees blossoming so full were affected, but why not those 

 that were not in bloom? It seems that the cell structure of the flowers is 

 somewhat different from the cell structure of the leaf, and appear more like 

 the cells of the cambium layer, or cells that form the bud and.new wood from 

 the evaporated sajD. It mast contain more or less starch, and the action of 

 the heat converting it or thickening it, forming a sort of glucose, and fer- 

 mentation follows at perhaps a lower temperature than is required in the 

 structure of the leaf. 



Now here is a cause of blight where no parasitic fungi, or spores of fungi, 

 or even bacteria, could have anything to do with it so early in the season, but 

 it set in as soon as fermentation commenced. The leaf turns dark and iinally 

 black, the rotten sap or poisonous fluid runs down the petal to the calyx, 

 along the little apple, then the stem of the little apple to the base, where all 

 the fruit stems started out of the flower-bud, and then all are affected, if they 

 had not been before. On most of the apple trees it only runs down to the 

 old wood and stops there, while on the crab or pear it is apt to run down the 

 older wood, and so extend until the tree is killed. 



A tree we will compare to the city water-works, and call the cells formed 

 from the last year's cambium layer in this tree, clear in the roots below ground, 

 the suction or supply pipes, the body of the tree the pump, the warmth and 

 sunshine the pump buckets, as the roots or rootlets act like a sponge, and 

 draw in the water, warmth, acting on the body and limbs and twigs of the 

 tree, works the buckets, or cells, which we will compare with a lot of glass 

 tumblers standing on toji one of another. The cells that were last formed 

 on the returning sap, or when the leaves dropped in the fall, are tumblers 

 right side up, and filled full with the ingredients to form the sap-wood. 

 Now, by the actions of warmth and sunlight, the cells, or tumblers, seem to 

 be uf)side down, or have upper and lower valves in the spring, and act like a 

 sucti©n-pump bucket, by which the water, or crude sap, is forced up into the 

 new leaves, which we will call the reservoir, where the pump forces it, and 

 where it is kept for the distribution and uses through the p'pes in all parts 

 of the city at any time, or where the action of the sun and air warm the 

 water, or crude sap, and evaporate, and fit it for the growth of the tree, or 

 wherever it is needed, either to form new wood, buds, or fruit and seeds. 



Although the water in the reservoir is calculated to supply the city at all 

 times, cold, freezing weather will sometimes burst the pipes; also, if the sup- 

 ply pipes are clogged or are injured by some cause, the pum])s (although 

 they are in good order) can not furnish a full sui)ply; or in hot weather, 

 more will collect and fill the distribution pipes and clog. The supi)ly is cut 

 off and repairs haveto be made, burst pipes replaced and others cleaned. 

 With the trees, the leaves are the reservoir. The water is held in round 

 globules, like round balls laid clo.se togethrr. These are covered on the uj)- 

 per surface with a thin air-tight film or. skin, but the lower side is open, or 

 held together with a net-work like a fine spider web, where the air can come 

 in contact with the globular cells and the little hair-like tubes act like valves. 

 They swell and shrink. ;ind close uj) in dam]) an<l fold weather })y swelling. 



