VIEWS OP LAMAECK 370 



environment and of the use and disuse of organs upon plants 

 and animals living in a state of nature : 



" The following fact proves, with regard to plants, how much 

 the alteration of any important factor in the environment 

 modifies the parts of these living bodies. 



" So long as Ranunculus aquatilis is sunk beneath the surface 

 of the W 7 ater, its leaves are all finely divided and have their 

 divisions hair-like ; but when the stems of this plant reach the 

 surface of the water, the leaves which develop in the air 

 become broadened, rounded and simply lobed. If some runners 

 of the same plant succeed in pushing their way into a soil which 

 is merely damp, without being inundated, their stems are then 

 short, and none of their leaves are divided into hair-like 

 segments ; thus arises Ranunculus hederaceus, which botanists 

 regard as a species when they come across it." l 



" With regard to habits, it is curious to observe the result 

 thereof in the remarkable form and in the stature of the giraffe 

 (Camelo-pardcdis) : we know that this animal, the tallest of the 

 mammals, inhabits the interior of Africa, and that it lives in 

 places where the earth, almost always arid and without herbage, 

 obliges it to browse on the foliage of trees and to make con- 

 tinual efforts to reach it. As a result of this habit, maintained 

 for a long time in all the individuals of its race, the fore limbs 

 have become much longer than the hind ones, and the neck has 

 become so much elongated that the giraffe, without standing 

 up on its hind legs, raises its head and reaches a height of 

 six metres (nearly twenty feet)." 2 



The following passage must suffice to give some idea of 

 Lamarck's views on the inheritance of " acquired " characters, 

 which his theory necessarily implies, though not in the 

 exaggerated sense of some modern writers : 



" These familiar facts are surely well suited to prove what is 

 the result of the habitual use by animals of some particular 

 organ or part ; and if, when we observe, in an animal, an organ 

 specially developed, strong and powerful, anyone pretends that 

 its habitual exercise has caused it to gain nothing, that its 

 continued disuse would cause it to lose nothing, and that, in 

 short, this organ has always been as it is since the creation of 

 the species to which the animal belongs, I would ask why our 

 domestic ducks can no longer fly like wild ducks ; in a word, I 

 would cite a multitude of examples relative to ourselves, which 

 bear witness to the differences which result in our own bodies 



1 Op. cit., Tom. I, p. 230. 

 a Ibid., pp. 256257. 



