200 



J. A. HARRIS AND R. A. GORTNER 



The discovery of this phenomenon was quite incidental.'' The 

 methods of demonstration are two: The comparison of the per- 

 centage of mature abnormal fruits in successive collections, and 

 the comparison of the relative numbers of abnormal fruits in 

 collections of fruits which are in a partially developed condition* 

 with those which are fully matured and are consequently older. 

 Numerically the results are therefore rough but quite sufficient for 

 first approximations. 



II. PRESENTATION OF DATA 



Consider first two series of plants belonging to a strain which 

 has been under cultivation at the Station for Experimental Evo- 

 lution since 1908. These comprise 24 and 25 individuals which 

 were transferred into 12-inch pots^ plunged in the garden. The 

 first lot contained garden soil. The second had in addition 175 

 grams of bone meal per pot. 



TABLE 1 



DATE OP COLLECTION 



NUMBER OF FRUITS 



August 19 



August 25 



September 10-11. 

 September 26-27. 

 October 6 



275 



135 



3,640 



6,519 



3,096 



NUMBER 

 OF ABNORMALS 



59 



24 



423 



398 

 203 



PERCENTAGE 

 OF ABNORMALS 



21.45 



17.78 



11.62 



6.11 



6.56 



For the normal soil series the results for different collections 

 of mature fruits are shown in table 1. There is a constant de- 

 crease in the percentage of abnormality from the first to the 



' These results were secured in a series of experiments initiated in the summer of 

 1918 to ascertain whether it is possible by the control of various external conditions 

 to modify the percentage of abnormal fruits, either as a whole or with respect to 

 some particular characters. This problem involves many technical difficulties 

 which render it undesirable to draw any final conclusions at the present time. 



^ These would unquestionably show all the abnormalities of the fruit wall. We 

 believe they are quite old enough to show prolification if it is to occur. 



^ All of the plants discussed in this paper were germinated under glass and 

 allowed to make their first growth in three-inch pots. 



