Gilbert: The Science of Genetics 



237 



THE FIRST MUTATION ON RECORD 



At the right is the Greater Celandine (Chelidonium majus) a plant of the poppy family 

 found in Great Britian and throughout Europe. At the left is a "sport," or mutant form, 

 markedly different in the shape of the leaves, which appeared in 1590. vSuch sudden 

 changes or mutations in plants and animals have been widely studied since the declaration 

 of De Vries, at the beginning of this century, that evolution was mainly due to them; and 

 they are still the subject of continual debate among genetists. Their origin is so mysterious 

 that many biologists think they may be merely the effects of undiscovered hybridization 

 in the ancestry of the plant producing them. All attempts to produce mutations experi- 

 mentally have failed. (Fig. 1.) 



theory was again remodeled to cover a 

 succession of creations extending down 

 almost to the present day. 



After the middle ages, evolutionary 

 theories were again revived, first by the 

 natural philosophers and rashly specu- 

 lative writers and finally by the working 

 and observing naturalists. The climax 

 was reached in the work of Lamarck 

 and finally of that greatest of natural- 

 ists and philosophers, Charles Darwin. 



THE influence OF DARWIN. 



The publication of the "Origin of 

 Species" had a profound influence upon 

 thought in all fields of human learning, 

 but more especially in biology. The 

 work of Darwin made such a deep 

 impression upon biologists, in fact, 



that problems of evolution were con- 

 sidered to be settled for all timie. For 

 nearly thirty years inquiry into the 

 methods of evolution was almost at a 

 standstill. 



This long silence was broken, however, 

 in 1900, when Hugo De Vries, a Dutch 

 botanist, published his monumental 

 work, "Die Mutations Theorie." Many 

 years before, it had seemed to De 

 Vries that Darwin's hypothesis of the 

 origin of species by natural selection 

 and the gradual acctimulation of varia- 

 tions was inadequate to explain all of 

 the facts, and that the method - of 

 origin as postulated by Darwin was- too 

 slow to account for the origin of our 

 present species within geological time. 

 For the purpose of proving whether 



