260 



lock: 



derived from grains which showed more or less purple pigmen- 

 tation in the ale mono layer : — 



1 



4 

 5 



Ci 



I 



s 



'.) 



Id 



II 



IL' 



i:t 



14 

 15 



1). 



17 

 18 

 li) 

 20 

 21 



a . 



w u 



G ® 



(D Si 



® s 



.'} 1 



3 3 



3 4 



3 5 



3 « 



1 4 



9 4 



'.♦ r> 



i:? 1 



i:t -1 



W, 3 



<.t 3 



it 1 



•» 2 



I I 



1 2 



1 3 



13 4 



2 1 



14 3 

 H I 





511 

 351 



279 

 110 

 5(5 

 30() 

 3G1 

 240 

 1.S9 



120 

 208 

 138 

 183 



55 



255 



(i5 



00 



88 

 77 



a ® 

 ^ 2 



a C 

 P-i S 



20; 



180 



35 



10 

 53 



o 



120 

 94 

 40 

 11 

 55 

 95 

 04 

 47 

 59 

 28 



182 



88 

 108 



37 

 129 



48 



259 

 205 



o 



;> 



a, 



100 

 74- 



77- 



O 4i 





4 

 2 

 73 1 



20 

 42 



34 

 10 

 25 



8 



132 

 29 

 34 

 15 

 55 

 11 



230 

 32 



83 

 80' 



72' 

 71 



76 • 

 75-9 

 7()-9 

 59-7 



00-8 

 55-8 

 51-5 

 58-1 

 52-4 

 24-7 

 23 1 

 29 1 



p 

 p 

 p 

 p 

 p 



20-7 P 

 30-0 P 

 340 P 

 180 P 

 29 • 9 P 

 22-3 P 

 P 

 P 

 24-8 P 

 240 P 

 28-9 P 

 29-8 P 

 180 P 

 W 

 110 Y 

 22 P 



Inspection shows that the entries in the table fall into a 

 number of groups. 



The first entry clearlj'^ represents a purple houiozygote. 



Entries 2 to 11 show percentages of purple gi'ains ranging 

 anmnd 75 per cent. Adding all these entries together we get 

 a total of 2,29(5 purple to 752 non-purple, or 75*3 per cent, of 

 purple — evidently a 3 : 1 ratio (expectation 75 d: '52 per cent.). 



Entries 12 to 18 show values ranging around 50*25 per cent. 

 The total obtained by adding up these entries amounts to 1 ,159 

 purple and HOH non-purple, or 57 "3 per cent, of purple. There 

 can 1)0 little reason to doubt that this correctly represents a 

 9 : 7 ratio (cxjiectation 5()-25 db '75 per cent.). 



All tlie above are the produce of the self-fertilized offspring 

 of i)urple grains. Entries 19 and 20 show the offspring of non- 

 purple grains, and these include ajjproxiraately 25 per cent, 

 of purj)l('s. It is, therefore, necessary in these two cases to 

 Hup[)080 cither that non-purple \\i\h suddenly become domi- 

 nant over purj)le, or that an inhibiting factor is present. 

 The latter supposition , which is the one adopted by East and 



