132 PLANT DISEASE 



quate supply of chlorophyll, and the conse- 

 quent loss or deficiency of the power of assimi- 

 lation." 



In other words, the parasitic fungus will 

 only thrive if the proper food be provided for 

 it. Now fungi are recognized by all authorities 

 as totally wanting in chlorophyll. 



The following extract may be taken as 

 illustrative of many others under Schizomy- 

 cetes, Webster's definition of which is " a group 

 of vegetable micro-organisms which are de- 

 void of chlorophyll as bacteria, micrococci, 

 etc." 



In Encyclopaedia Britannica, vol. xxi., p. 406, 

 under Schizomycetes, under nutrition, " Hav- 

 ing no chlorophyll." 



This being so it is an obvious deduction that 

 the plant (or animal) on which they thrive is 

 also so deficient, and this seems to settle the 

 question as to whether the parasite produces 

 the disease, or is a symptom of it. It would of 

 course be folly to maintain that no organic 

 deterioration takes place in the plant (or 

 animal) after the appearance of the fungus. 



In fact, as Professor De Barry says in his 



