242 BIOLOGY: GENERAL AND MEDICAL 



The writing was discovered in 1900 by de Vries, who 

 called attention to its great importance, excited interest 

 in Mendel's problems, and aroused such enthusiasm 

 among scientists generally that the paper was translated 

 and republished with an introductory note by W. 

 Bateson in the Journal of the Royal Horticultural Society 

 of London, Vol. XXIV, 1901-02. 



In considering Mendel's work it must not be forgotten 

 that it is a study of hybrids and that in consequence all 

 that was found need not apply to normal reproduction, 

 but it must be remembered that hybrids, through the 

 striking dissimilarities of their parents, some of which 

 are combined in the offspring, enable us to trace given 

 characteristics with ease because of their conspicuousness. 

 It is the ability to recognize the Mendelian characters 

 that has made it possible to formulate a law as to their 

 mode of transmission. 



Mendel worked with peas because the sexual organs of 

 these flowers are enclosed by the petals in such manner 

 that self-fertilization is inevitable. To make the hybrids, 

 he had to cut away part of the flower, remove the unripe 

 anthers, and at the time of the maturation of the stigma 

 apply such pollen as was desired. 



It was soon discovered that certain characters of 

 the peas were traceable from generation to generation, 

 appearing in recognizable form in the normal individual 

 and in the hybrid. Such characters are, for example, 

 color of the flower, size of the plant, quantity of sugar 

 in the seed, and quantity of starch in the seed. These 

 characters which appear to blend with their opposites in 

 the hybrids of the first generation are found by an 

 examination of the second generation to have effected 

 a temporary combination which loosens up and begins 

 to separate, so that with each succeeding generation a 

 greater number of the offspring revert to the parental 

 types until after, say, ten generations scarcely any hybrid 

 organisms remain. 



These facts were in thorough accord with well-known 



