1914] /. Arthur Harris and Ross Aiken Gortner 201 



the combined series in Diagram i (Plate 2). A comparison of these 

 constants, both in the tables and in the graphs will, we believe, con- 

 vince the reader that there is no close interdependence between 

 either the weight (see Diagram 2) or the number of seeds (Diagram 

 I ) of a pome and the physico-chemical properties of the expressed 

 Juices of practically matured fruit. 



Summary. In apples and pears, as in C er eis and Staphylea, 

 there is a material correlation between the size of the fruit and the 

 number of seeds which it produces. Various considerations render 

 it probable that the relationship is a direct causal one and that the 

 size of the fruit is influenced by the number of seeds, rather than 

 conversely. 



The first Suggestion concerning the mechanism of this relation- 

 ship would seem to be that the development of the seeds influences 

 in some way the physico-chemical properties of the sap in the devel- 

 oping fruit. We have, however, been unable to demonstrate any 

 sensible differences in the osmotic pressure, mean molecular weight, 

 or electric conductance of the saps of nearly ripe fruits of different 

 sizes or producing different numbers of seeds. These findings do 

 not preclude the possibility that in the earlier developmental stages 

 of the fruit such differences may exist. 



EXPLANATION OF DIAGRAMS, PLATE 2 



DiagraDi i: Comparison of physico-chemical constants of the sap of pears 

 producing various numbers of seeds with the slope of the straight line (with 

 empirical means) showing increase in weight of the fruit with increase in number 

 of seeds per fruit. 



Diagram 2: Physico-chemical constants of pears of various weights. 



In neither case is there in the trend of the values any clear indication of 

 relationship between the size of the fruit or the number of seeds which it pro- 

 duces and the constants determined. In both diagrams the significance of the 

 Scale to the left dififers from constant to constant. The complete data are given 

 in the tables. 



