LIFE AND ITS PHENOMENA 55 



This is better adapted for a harder soil, while the 

 incisors can nibble short grass, as on downs ; and it does 

 not require the use of the tongue for " licking " up the 

 grass. 



Huxley said somewhere that even if such Lamarckism 

 were true, it could only apply to half the living world ; 

 but he was not then aware that " use and disuse " are 

 equally applicable to the vegetable kingdom. 



Thus, if weights be attached to young parts of plants, 

 as growing shoots or leaf-stalks, just insufficient to break 

 them, they soon acquire a much greater strength than 

 they would have done, had they been not so weighted. 

 Thus, e.g., the little stem of a seedling sunflower, 

 which would have broken under a weight of 160 grms., 

 bore a weight of 250 grms., after having been subjected 

 to a strain of a weight of 150 grms. for two days. The 

 weight was subsequently increased to 400 grms. without 

 injury. Leaf-stalks of the Christmas rose, which broke 

 with a weight of 400 grms., were able to resist one of 

 35 kils., after having been subjected to a strain for five 

 days.^ 



Wood is formed more or less in most stems growing 

 in the air, to resist the strain of gravity. But in aquatic 

 plants, since the water supports the submerged parts as 

 well as air within them, the stem ceases to form wood 

 by " disuse," since it is no longer called upon to support 

 itself. 



The bodies of animals and plants are thus living 

 automata. Their protoplasm spontaneously responds 

 in hundreds of ways to whatever stimulus comes from 

 without, and the response evinces itself, as if by an im- 

 material Directivity which meets the irritations, environ- 



^ I am here quoting from my book, The Origin of Plant Structures, 

 p. 204, where further illustrations will be found. 



