CONTROL OF PLANT DISEASES 



475 



years 1846 and 1864, notwithstanding the fact that the first sulphur 

 treatment for powdery mildew was recommended in 1821 and the first- 

 seed treatment for smuts was discussed in 1807. 



Ancient 



Medieval 





1700 



1850 



1870 



] 



1890 1 1900 



1910 































Foot & Mouth 





Tuberculosis 





























































Black Leq 











Rabies 







































Tetanus 













































Hoq Cholera 





Texas Fever 





























Actinomycosis 

























Glanders 



















Anthrax 





















— 







Table II. Showing Advance in Knowledge regarding some of the Chief 

 Diseases of Domestic Animals. The broken upper line indicates vague or indefinite 

 knowledge ; the solid line definite knowledge. The lower broken line indicates partial 

 but unsatisfactory knowledge concerning treatment : the solid line the possession of 

 facts sufficient for satisfactorv treatment. 



Ancient Medieval I70o'i85o 1870 



1890 1900 1910 



= Tuberculosis 

 =| Small Pox 



; Diphtheria 

 :Hook Worm 

 : Malaria 



Cancer 



Yellow Fever 



Bubonic Plaque 



Pneumonia 

 ; Typhoid Fever 



: Cholera 



Bnqhts Disease 



Sleeping SicKness 



=j Whoopinq Couqh 



Table III. Showing Advance in Knowledge regarding some of the Chief 

 Human Diseases. The broken upper line indicates vague or indefinite knowledge ; the 

 solid line definite knowledge. The lower broken line indicates partial but unsatisfac- 

 tory knowledge concerning treatment ; the solid line the possession of facts sufficient 

 for satisfactory treatment. • 



