144 PLANT DISEASE 



It would be at least an interesting experi- 

 ment to see which would win. 



I wish to make it clear at this point that 

 while the want of iron in the chlorophyll or 

 haemoglobin is always associated with chlorosis 

 or anaemia it should also be remembered that 

 a want of nitrogen or, what follows, of carbon 

 brings about much the same condition of 

 things. 



In fact, the want of one more or less involves 

 the want of the others ; therefore chlorosis or 

 anaemia cannot be accurately described as a 

 deficiency of iron in the plant or animal, as 

 the absolute want of potash in the soil will 

 prevent the plant from assimilating either 

 iron or phosphoric acid in the way it should, 

 and the same deficiency will prevent the move- 

 ment of starch in the plant. 



This will cause the plant to be defective in 

 nitrogen, consequently chlorotic, and wanting 

 in chlorophyll and all the carbon com- 

 pounds. 



I have written on this point at some length 

 in order to make it clear that a deficiency of 

 one element upsets the whole chemistry of the 

 plant, and must act more or less in the same 



