68 PLANT DISEASE 



in one direction, namely, that if the tissues 

 are maintained in normal health they form a 

 very resistant barrier against bacteria." 



The Origin and Growth of the Healing Art, by 

 E. Berdoe, L.R.C.P., Edin., M.R.C.S., Eng., 

 etc., on page 475 says 



" It has been found that men and animals 

 may be insusceptible to infective disease by 

 natural immunity. Not all persons subjected 

 to exposure to epidemic diseases contract 

 them." 



The passages above quoted show that it is 

 admitted that the proteids are fatal to patho- 

 genic bacteria, and that the carbohydrates, 

 fats, and proteids of the plant are dependent 

 on the chlorophyll. 



It is well recognized that the chlorophyll 

 of the plant varies considerably, therefore the 

 carbohydrates, fats, and proteids of the plant 

 must vary in a like proportion, and as animal 

 life can only obtain its carbohydrates, fats, 

 and proteids through the vegetable food eaten, 

 they must vary consequently in the animal 



