Ill MENDEL'S WORK " 25 



Mendel, however, could not have known of this, and 

 his inability to discover in Hieracium any indication 

 of the rule which he had found to hold good for 

 both peas and beans must have been a source 

 of considerable disappointment. Whether for this 

 reason, or owing to the utter neglect of his work by 

 the scientific world, Mendel gave up his experimental 

 researches during the latter part of his life. His 

 closing years were shadowed with ill-health and 

 embittered by a controversy with the Government on 

 a question of the rights of his monastery. He died 

 of Bright's disease in 1884. 



Note. — Shortly after the rediscovery of Mendel's paper 

 a need was felt for terms of a general nature to express tlje 

 constitution of individuals in respect of inherited characters, 

 and Bateson accordingly proposed the words homozygote 

 and heterozygote. An individual is said to be homo- 

 zygous for a given character when it has been formed by 

 two gametes each bearing the character, and all the gametes 

 of a homozygote bear the character in respect of which it is 

 homozygous. When, however, the zygote is formed by 

 two gametes of which one bears the given character while 

 the other does not, it is said to be heterozygous for the 

 character in question, and only half the gametes produced 

 by such a heterozygote bear the character. An individual 

 may be homozygous for one or more characters, and at 

 the same time may be heterozygous for others. 



