A "Use" for Everything 133 



the teacher promptly, "but I am sure that it has 

 something with which to protect itself." 



Thereby I knew her point of view: she had 

 made up her mind what to see, and it was neces- 

 sary only to hunt until she saw it; and in this 

 respect she was like many another. Persons 

 seem to interpret the struggle for existence as 

 a fight. It is a sanguinary combat between 

 adults. Everything must protect itself with 

 armor. A botanist, in writing a description of 

 a new and strange plant, noted the peculiar 

 spines and then remarked: "That these are of 

 some use to the plant can hardly be doubted. 

 Perhaps they serve to prevent the access of 

 undesirable insects." 



Nothing is easier than to find an explanation 

 for anything; the only difficulty is to determine 

 whether the explanation is true. I have just 

 read in an old book that the reason why a par- 

 ticular kind of graft failed to grow was because 

 of the "disappointment of the sap." I laughed 

 at the expression; and yet is it not as scientific 

 as to say that the hairs exist to keep the crow- 

 foot warm or that the sumac has poison to pro- 



