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Page 



Lodging of grain 662 



Lack of light as predisposition to disease 666 



Chapter XIV. Excess of light 671 



Section 3. EXZVMATIC DISEASES. 



Chapter XV. Displacement of enzymatic functions 675 



General discussion 675 



Albinism (Variegation) 677 



Mosaic disease of tobacco 684 



Pox of tobacco 689 



White rust of tobacco 690 



Disease of tlie peanut in German East Africa 690 



Shrivelling disease of the mulberry 690 



Sereh disease of the sugar cane 692 



Cobb's disease of the sugar cane ^96 



Peach yellows 697 



Gummosis of the cherry 699 



Exudation of gum in other plants 707 



Exudation of gum in the Acacia 707 



Gummy exudation of the bitter orange 708 



Black-leg of the edible chestnut 709 



Gummosis of the fig tree 710 



Exudation of manna ~ii 



Resinosis .... 7 r i 



Formation of resin in dicotyledonous plants 716 



Section 4. EFFECT OF IN'JURIOUS GASES AXD LIQUIDS. 



Chapter XVI. Gases in smoke 718 



Sulphurous acids 718 



Hydrochloric acid and chlorin 724 



Hydrofluoric acid 729 



Nitric acid 730 



.\mmonia 730 



Tar and asphalt fumes '/I2 



Bromine 735 



Chapter XVII. Solid substances given off by chinmeys and the distillates they 



contain .737 



Hydrogen sulfid 742 



Soda dust 743 



Control plants 744 



Illuminating gas and acetylene 744 



Chapter XVIII. Waste water 748 



Waste water containing sodium chlorid 748 



Waste water containing calcium chlorid and magnesium chlorid 751 



Waste water containing barium chlorid 752 



Waste water containing zinc sulfate 752 



Waste water containing iron sulfate 753 



Waste water containing copper sulfate and copper nitrate 754 



Chapter XIX. Injurious effects of cultural methods .756 



Coating substances 756 



.Anaesthetica 765 



Injuries due to fertilizers "jd-j 



Section 5. WOUXDS. 



Chapter XX. Wounds to the axial organs 772 



General discussion 772 



Scarification wounds 776 



Inscriptions 781 



Injury due to wild animals 781 



Overgrowth of cross wounds in many-year-old trees 783 



Overgrowth processes in year-old branches 785 



Girdling callus 787 



