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pathologists using the names of the human pathologist and the physician. 

 They speak of "epidemics"' and "endemics" among plants — those terms 

 etymologically refer to people, meaning "upon the people" and "among the 

 people". It seems rather incongruous to use such terms for diseases upon 

 or among plants. But it is facts, not words, that scientists are after. 

 Then there occur such names as chlorosis, icterus, atrophy, necrosis, and 

 even cancer and consumption. 



Plants are aiflicted with diseases due to hacteria, to fungi (even to 

 higher, flowering, plants), to animal and vegetable parasites of all kinds, 

 to mites and worms, just as human beings. Bat, perhaps needless to say, 

 the species are different. Although some of the common names current 

 among physicians are used, yet the scientific names are wholly different. 

 Another thing that impresses one on going through the books on plant 

 pathology is the importance attached to cleanliness, as cleanliness about 

 the orchard, destroying dead branches and leaves and keeping the grouiul 

 and trunk clean, the necessity for spraying and fumigating, measures that 

 physicians lougiago learned but which the people are slow to adopt. Thar 

 cities need as careful. attention as orchards seems to be known to but few 

 of the people. The old farmer must be told why his orchard does not 

 flourish, why trees are sickly and ultimately die, just as many a com- 

 munity must be told \\'hy its people are siclvlj- and why there is race 

 suicide. 



One day while botanizing I came across a field thickly overgrown with 

 Iron Weed and A'ervain. At one end it was "net and swampy, with pools 

 cf water. The farmer, who was plowing, overtook }ne. We engaged in con- 

 versation. I asked him vrhy he allowed those weeds to grow. "The cows 

 like weeds ; they brush off mosquitoes and flies." He thought this sufficient 

 reason for allowing weeds to grow. I pointed out how flies breed in his 

 manure pile and that by giving a little attention the number of flies could 

 be greatl.v reduced ; that mosriiiitoes bi-eed in wet places, as at the end of 

 the field, and that with a little drainage the mosquito pest could be pre- 

 vented; that with flies and mosquitoes absent there would be no need for 

 the vi-eeds ; with fewer flies the cows wasted less energy in switching them 

 and would give more mill< : .'.nd in the absence of blood-sucking mosquitoes 

 would gain in flesh. In tlie absence of weeds there would not Ite a con- 

 stant cloud of seed blowing on to liis cuKivated fields and on to those of 

 his neighbors. 



