320 THE SIGNIFICANCE OF SEXUAL REPRODUCTION 



was there any reason to suppose that the characters transmitted were 

 really acquired. For example, Fritz Miiller has recently informed 

 me of an instance in which he believes that there can be no doubt 

 of the transmission of acquired characters. His observations are 

 so interesting in several respects that I will quote them here. He 

 says in his letter, ' Among the bastards of two species of Alutilon, 

 in which I had never observed hexamerous flowers, there was 

 a single plant with a few such blossoms. As these flowers are 

 sterile with the pollen of the same plant, I was obliged to fer- 

 tilize it with pollen from another plant bearing only pentamerous 

 flowers, in order to obtain seeds from the former. For three weeks 

 I examined all the flowers from a plant grown from such seed, 

 finding 145 pentamerous, 103 hexamerous, and 13 heptamerous 

 flowers. I examined similarly the flowers of another plant pro- 

 duced from seed obtained from pentamerous flowers from the same 

 parent plants. There were 454 pentamerous and 6 hexamerous 

 flowers, and hence only 1*3 per cent, of the latter kind.' 



It must certainly be admitted that the large proportion of ab- 

 normal hexamerous flowers depends upon heredity in the instance 

 first quoted ; but the hexamerous condition is not an acquired 

 character ; it is merely the first appearance of a new innate 

 character. It is not due to the reaction of the vegetable organism, 

 under some external stimulus, for it appeared in a plant exposed to 

 conditions similar to those which acted upon the other plant which 

 only produced the normal pentamerous flowers. It must therefore 

 have resulted from the tendencies which were present in the germ 

 from which the plant itself developed, either as a spontaneous 

 change in the germ-plasm or through the combination of two 

 parental germ-plasms a combination which may lead to the 

 appearance or the reality of a new character. We know that the 

 germ-plasm of each individual is not a simple substance, but pos- 

 sesses a very complex composition, for it consists of a number of 

 ancestral germ-plasms represented in very different proportions. 

 'Now, although we cannot learn anything directly about the pro- 

 cesses of growth of the germ-plasm, and its resulting ontogenetic 

 stages, yet we do know, chiefly from observations upon man, that 

 the characters of ancestors appear in the offspring in very different 

 combinations and in very different degrees of strength. This may, 

 perhaps, be explained by assuming that in the union of parental 



