iv LESAGE'S EXPERIMENTS 211 



principal cause of dimensional differences is then to 

 be found here. And lastly chlorophyll is less abun- 

 dant in shore-inhabiting individuals. These facts of 

 observation have been confirmed by experimental 

 facts. M. Lesage has cultivated plants of the same 

 species under precisely similar conditions save one, 

 and has found that the results concur with his obser- 

 vations. The one condition which differs between the 

 two sets of cultivations is the presence or absence of 

 common salt in the water used for watering the plants. 

 Of two individuals of the same species the one which 

 has grown in soil watered with salted water has thicker 

 leaves, and in these leaves the palisade cells are seen 

 to be larger and more numerous. The experiments 

 show that the influence exerted by sea-shore life 

 on plants is principally due to the salt which is always 

 contained in lesser or greater quantities in the soil, 

 and is brought there by the winds carrying small 

 drops of sea-water from the crests of the waves ; they 

 show at the same time that external variations are 

 accompanied by important structural differences. 



Sea-shore life or the presence of some common salt 

 in the soil where plants grow exerts even more im- 

 portant variations ; variations not in morphology 

 and anatomical features, but in the physiological 

 processes. In experiments concerning radishes M. 

 P. Lesage has seen that while in radishes watered 



P 2 



