SEED-NUMBER AND FRUIT-SIZE 333 



to which of the two sorts of fruits offers the best materials, 

 the moist or the dry, has to be answered with another query 

 as to whether the two results would be really comparable and 

 would possess a biological importance similar in degree and in 

 kind. 



As far as the dry fruit is concerned, it is requisite to 

 remember that we are here actually determining the relation 

 between a resting seed with its vitality suspended and a dried- 

 up and dead fruit-case. Whether it is a shrivelled berry or 

 a shrunken drupe, as in Ribes and Prunus, or a dried dehiscing 

 pod, as in Vicia, or a withered capsule, as in Iris and Canna, or 

 a woody dry capsule, like that of the Mahogany (Swietettia), 

 that on account of the abundance of ligneous tissue retains 

 the form of the moist fruit, makes no difference. The mere 

 retention of form in some dried fruits, as in certain kinds of 

 legumes and capsules, and its complete loss in others, as in 

 most drupes and berries, are merely accidents in the history of 

 the fruit. The investigator does not recognise the distinction 

 between moist and dry fruits in the living condition. For 

 him all fruits are moist in the living state ; and if, after the 

 drying up and death of the fruit-case, the form of the living 

 fruit is to some degree preserved, he will avail himself of the 

 circumstance only in so far as it assists him in his studies of 

 the living condition. 



It would therefore appear that the moist and the dry fruit 1 he data 

 are not mutually comparable, and that the only comparison of d^j.up 

 any biological value is one which enables us to reconstitute the fniitsare 

 living fruit, when the only materials at our disposal are its service when 

 dried-up remains. The loss in weight which the pericarp and the living 

 seeds of the living fruit undergo when dried in ordinary air- condition, 

 conditions can be ascertained by experiment, and the results 

 can be applied to the dry fruit. These shrinkage ratios, being 

 constant for the same species and independent of the size of 1 

 the fruit, do not, when applied, interfere with the progressive 

 scale of the weight-relations between the pericarp and the 

 seeds. In this sense, therefore, the data supplied by the dry 



