CHAPTER V. 



DISEASES. 



DIFFICULTIES IN THE OUTSET WHAT CONSTITUTES DISEASED ACTION 



NO ANALOGY TO ANIMAL SICKNESSES CONGENITAL DEFECTS 

 DEBILITY DEFICIENT STRENGTH OF FIBRES DEFECTIVE FOLIAGE 



IMPERFECT AND REDUNDANT BLOSSOMS THE CIVILIZED AND 

 CULTIVATED PLANT MAY BE ABNORMAL ALTOGETHER UNSATISFAC- 

 TORY ACCOUNTS OF DISEASES IN PLANTS LANKESTER'S CLASSIFICA- 

 TION CONSIDERED EFFECTS OF THE EXCESS OR PAUCITY OF MOIS- 

 TURE, HEAT, AND LIGHT MODE OF ACTION OF FROST INJURY 

 RATHER REFERRIBLE TO THE CONDITION OF THE CIRCULATION THAN 

 TO THE DEGREE OF COLD IN MANY HARDY PLANTS INFLUENCE OF 

 THE SOIL LIGHT THE GREAT STIMULUS, ITS WITHDRAWAL SUS- 

 PENDS HEALTHY ACTION ITS SUDDEN RESTORATION CAUSES DEATH 

 BY SUN SCALD INJURY BY SUNSHINE IN WINTER POISONOUS GASES 



MIASMATA POISONS IN THESOIL PARASITIC PLANTS, EPIPHITES, 

 FUNGI, PEAR BLIGHT VARIOUS THEORIES WHAT WE KNOW, AND 

 WHAT WE DON'T KNOW TREATMENT ROOT PRUNING SUGGESTED 



SATISFACTORY RESULTS MILDEW BLIGHT IN PEACH AND APPLE 



TWIG BLIGHT IN APPLE AND QUINCE THE APPLE BLIGHT 

 BITTER ROT CRACKED FRUIT SCAB MILDEWS KIRTLAND'S 

 VIEWS AND SUGGESTED REMEDY WOUNDS AND INSECTS NEEDING 

 THE AID OF SURGERY RATHER THAN MEDICINE DESTRUCTION OF 

 FOLIAGE BY INSECTS IMPAIRS THE HEALTHY CONDITION OF THE 

 PLANT RESUME SELECT HEALTHY TREES OF HEALTHY VARIETIES 



EMPIRICAL CHARACTER OF TREATMENT USUALLY RECOMMENDED 

 FOR DISEASED TREES THE BLACK KNOT THE ROT AND MILDEW 

 OF THE GRAPE. 



In opening a discussion upon the nosology of vegetation, 

 it may be expected that one who had spent many years 

 of his life in the investigation of the diseases of the human 



