THE PLANT AND ITS SURROUNDINGS. 3 



valuable information, and that lessons of impor- 

 tance are derived from comparisons of the 

 analyses of the ashes, etc., of plants ; but he 

 is no longer able to cherish the hope, however 

 remotely, that such studies solve his most im- 

 portant problems. 



The scene or rather the point to which atten- 

 tion is now directed is the living, working, energy- 

 accumulating plant itself, and not the dead store 

 of materials in the soil. The reason for the change 

 is not far to seek : it is due to the enormous strides 

 made in the study of the physiology of plants 

 during the last quarter of a century, and the sub- 

 ject abounds in examples illustrating the marvellous 

 advances that have been made, and at the same 

 time showing how, in the progress of researches, 

 made for their own sake i.e. in pursuit of satis- 

 faction for the intense curiosity of the scientific 

 man all kinds of side issues turn up which prove 

 to be of value in practice, and suggestive of further 

 thinking. 



At the beginning of the nineteenth century 

 i.e. about 1820 the best thinkers were giving up 

 the old ideas that the environment supplied food, 

 as such, to plants, and had recognised that the 

 plant takes up substances from without and re- 

 arranges these in its own body. 



The next twenty years or so form a very dark 

 interval in plant physiology, chiefly owing to the 

 influence of the assumption of a special "vital force," 

 an assumption which was not allowed merely to 

 serve as a hypothesis put forward to stimulate 



