96 LOCK: STUDIES TN PLANT RRKEDINO 



INTRODUCTION. 



r l THE present description of experiments with Indian corn 

 -*- (Zea Mays, L.) brings to a conclusion the account of a 

 series of experiments in cross breeding carried out at Pera- 

 deniya during the years 1 902-04. The results are for the most 

 part concerned with the foundations of the new Mendelian 

 science, rather than with any fresh developments ; and statistics 

 of considerable extent and uniformity are here brought forward 

 as a contribution towards the firmer establishment of the 

 original simple law, which describes the segregation of discon- 

 tinuous characters during the formation of the germ cells in 

 heterozygote plants. 



It is to be regretted that difficulties are still found to stand in 

 the way of our arriving at unanimity as to the use of the term 

 Mendel's law.* De Vries, in his latest utterance upon the 

 subject, employs the law of Mendel as a term to describe the 

 proportion in which the different types appear in F 2 from a 

 monohybrid, which he expresses in the form : — 1 A : 2 H : 1 L. 

 (A active, H hybrid, L latent.) 



Others again include the idea of dominance in their applica- 

 tion of the phrase Mendel's law. and the expression is often used 

 without definition. It seems necessary, therefore, to repeal 

 i hat in the present series of papers the term " Mendel's law " is 

 invariably used in the sense in which Correns first enunciated it , 

 namely . as applying to the fact that in the germ cells of a hetero- 

 zygote, the parental allelomorphs become segregated in all 

 possible combinations in equal numbers. It must once more 

 be insisted that, in cases of discontinuous inheritance, the only 

 examples where this rule has so far been proved not to be 

 followed are those in which correlation or coupling between 

 dilferent allelomorphs i^ found to occur— if we leave out of 

 account the little understood cases <>f supposed blended inheril 

 anoe 



* Of, VnnaU n., 305. Also Karl Pear a Nature, vol. 70, p. 627. 



