CHAPTER Y. 



DISEASES. 



niFFICn-TIES IN THE OUTSET — WHAT CONSTITUTES DISEASED ACTION 



— NO ANALOGY TO ANIMAL SICKNESSES — CONGENITAL DEFECTS — 

 DEBILITY — DEFICIENT STBENGTH 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 OP FROST — INJUET 

 RATHER REFERRIBLE TO THE CONDITION OF THE CIRCULATION THAN 

 TO THE DEGREE OF QOLD IN MANY HARDY PLANTS — INFLUENCE OP 

 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 KHOW, 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 COI>DITION OF THE 



PLANT — BHSUME — SELECT HEALTHY TREES OF HEALTHY VARIETIES 



f 



— EMPIRICAL CHARACTER OF TREATMENT USUALLY RECOMMENDED 

 FOR DISEASED TREES — THE BLACK KNOT — THE EOT 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 



