THE HEREDITY OF ACQUIRED CHARACTERS IN PLANTS. 79 



independent cases, among plants of no affinity, and situated in diverse 

 parts of the world, whether on land or in water ; so that there arises a 

 "moral conviction" that there are to be seen distinct causes and effects. 

 This line of argument leads one to the conclusion that it is infinitely 

 probable that drought and water are the respective causes. It is the 

 argument accepted by physicists who believe they know the elements in 

 the sun, but they cannot experiment upon the sun itself to corroborate 

 their inductive evidence, supplied by the spectroscope. Astronomers 

 believe that the earth rotates on its axis to produce day and night ; but 

 they cannot prove that the sun does not go round the earth in twenty- 

 four hours. It is solely that it is infinitely more probable that the earth 

 should rotate than that the sun should go round it. The result is not a 

 mathematical demonstration, but a moral conviction. 



If now the peculiarities of plant-structures were acquired in response 

 to the action of the environment, then it is obvious that they are 

 hereditary. 



Although inductive evidence is really ample to substantiate the belief, 

 it has been thoroughly corroborated by experimental verification. Indeed, 

 we need not go beyond the kitchen garden, for if we compare our Carrots, 

 Radishes, Parsnips, all the Cabbage tribe, &c, with the wild plants from 

 which they have been derived, we see at once that their peculiarities, 

 confined as they are to the vegetative system or soma, are all acquired 

 characters, and arose by the stimulating action of a rich and artificially 

 prepared garden soil. 



There is no question of germ-plasm of the reproductive organs being 

 concerned in it ; because the enlarged roots, the altered forms of " greens," 

 Brussels Sprouts, Kales, even Cauliflowers, are all formed long before the 

 reproductive organs put in any appearance at all. Yet w,e know that these 

 garden forms of acquired somatic characters are hereditary, for they all 

 come true by seed. 



Turning back to the question, " Will plants transmit any acquired 

 character to the first generation ? " the answer is, judging by horti- 

 cultural experience, any new character which the cultivator wishes to 

 preserve must be perpetuated by selection and by using the same 

 external conditions of soil, &c, for five or six years before he can 

 depend upon its fixity. As a rule one year is not enough. Neverthe- 

 less, it sometimes happens that variations arise which are permanent 

 from the first year of their appearance, as has occurred with certain 

 strains of Chinese Primrose, species of Oenothera, &c. It is not, 

 therefore, a fair question to ask for proof that any character acquired in one 

 year shall be transmitted to the first generation ; and that too, wherever 

 the offspring may happen to grow. Nature demands accumulation 

 under the same conditions, till fixity can be trusted and heredity secured. 



" Everything tends to become hereditary," * says a writer on garden 

 varieties, but everything must, as a rule, be encouraged for a few years, 

 when Nature responds to the care of the cultivator and fixes the 

 variation. 



Though cultivation supplies us with ample evidence to prove the fact 



* Production at Fixation des VarUUs dans les Vtgctaux, par E. A. Carriere; 

 p. 9, 1865. 



