138 PLANT DISEASE 



And as the percentage of iron varies from, 

 say 16 per cent, to *ooo, it is easy to under- 

 stand how the carbon, hydrogen and nitrogen 

 may vary, which will account for the variation 

 in the percentage of proteids as found in corn 

 at the Illinois station. 



And to try and fix the proteids by inherit- 

 ance is in the main waste of time, for if corn 

 rich in proteids be sown in a poor soil for a few 

 years consecutively, we shall see a rapid dis- 

 appearance of the same. Otherwise, how is 

 it that an inferior soil, after being sown to 

 wheat for a few years, will return a yield less 

 in quantity than and inferior in quality to the 

 seed sown. 



As vegetable fats are thought to be pro- 

 duced direct from the carbohydrates, it is 

 easy to understand how they are governed by 

 the same law. 



As the fats are deficient and vary in rice 

 and corn, and knowing that other foods grow 

 under the same laws, it is reasonable to assume 

 that the nitrogen and fats of other foods vary 

 in the same way. Rice as a food is recognized 

 as being poor owing to its deficiency in nit- 

 rogen and fats, and considered conducive to 



