2 CULTURE OF THE SWEET PEA 



ever, have singled out on plants parasitic 

 organisms whose work brings about devi- 

 ations from the normal. To-day Plant 

 Pathology has become recognized as a 

 definite science. There is hence no reason 

 why we should tolerate certain plant dis- 

 eases when we realize the vast store of 

 scientific knowledge available. Indeed it 

 is highly imperative that any man who is 

 engaged in the growing of crops should be 

 able to recognize a diseased condition in 

 plants. 



Like every science, Plant Pathology has 

 made slow progress in its beginning. 

 Scholars who considered it from a purely 

 speculative or philosophical point of view 

 only were interested in it at first. It was 

 really during the first half of the nine- 

 teenth century that Plant Pathology built 

 for itself a solid foundation, and gained 

 a place among the leading sciences. It 



