CHAPTER XVII. 



REMEDIAL MEASURES. 



Preventible diseases The principles of therapeutics 

 Powders and their application Spraying with 

 liquids Nature of chemicals employed Employment 

 of epidemics and natural checks The struggle for 

 existence. 



It may be said that in no connection is the 

 proverb " Prevention is better than cure "' more 

 apph'cable than with this subject, and undoubtedly 

 the best utilitarian argument that can be used in 

 favour of a thorough study of the causes of 

 disease is that only by understanding these causes 

 is there any hope of avoiding the exposure of 

 crops, garden plants, forest trees, etc., to the 

 attacks of preventible diseases. Moreover, only 

 an intelligent appreciation of the causes of a 

 disease will enable the cultivator to take steps 

 to mitigate their effects when once the damage 

 has begun its course. Every cultivator learns by 

 experience or by precept that there are some 



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