160 THE NATURE-STUDY OF PLANTS 
their predecessors, and then by the addition of his 
own, his acquired information will rise to the higher 
level of personal knowledge, whether the induction 
be modified or not. 
It is in this way and in this way alone that a 
correct mental picture of the subject in hand can be 
acquired, clear and with the details in true perspective, 
that progress in Science is achieved and its accuracy 
enhanced. The more one knows about the natural 
history of plants the more surely does one realize 
that they are not hidebound by hard and fast rules of 
conduct. As we have seen, neither the Herb Roberts 
on the shingle nor the Storksbills in the shade behave 
in all particulars like their fellows in the moist hedge- 
row and on the dry sunny heath respectively, while 
the hairiness of the Shining Cranesbills which came 
under my own observation seems to be an unusual - 
feature; plants, like animals and human beings, 
react in response to a change of circumstances, and it 
is apparently in that way, although not in that way 
alone, that new forms appear and new species become 
established. 
When, therefore, the student finds that his obser- 
vations do not agree with those of other people, he 
need not conclude that there has been a mistake 
in his or in anybody else’s work, even in the face of a 
flat contradiction. The better part is to make quite 
sure of his own results and to confirm them by repe- 
tition, for it is just as likely, and if both observers be 
careful a great deal more likely, that neither of them 
has erred, but that the different results are due to 
the different surroundings of the individual plants 
observed. 
I advocate neither cocksureness nor diffidence, 
