WHAT IS A GEAPE? 249 



Looking 1 closely into my cluster of grapes, again, 

 I see that it still contains two or three unripe and 

 stunted specimens. These, of course, are pale-green, 

 like the leaves, and when I taste one of them I find it 

 unpleasantly harsh and acid to the palate. This 

 reminds me that grapes, like other fruits, are not at 

 all stages of their existence sweet and brightly 

 coloured. While the seeds are still immature, they 

 would only lose by being eaten, because they are not 

 yet fit for germination. In this stage, therefore, the 

 skin is filled with green colouring matter, and the- 

 cluster is quite inconspicuous among the foliage which 

 surrounds it. It does not want to attract attention 

 in its present stage. Furthermore, the pulp at this 

 period is filled with tartaric acid and other sour juices, 

 to repel any too-inquiring or too-impatient visitor. 

 But as the seeds mature, the fruit ripens, that is to 

 say, a chemical change goes on in the pulpy portion, 

 which results in the formation of grape-sugar. At the 

 same time other chemical changes taking place in the 

 skin result in the production of the purple bloom, 

 which advertises to the birds the presence of the 

 sweet juice within. The whole process obviously aims 

 at concealing the fruit and rendering it unpalatable 

 while the seeds are immature, and at making it con- 

 spicuous as well as pleasant the moment the seeds are 

 ripe for dispersion. Hence we are justified in con- 

 cluding that the development of the grape is due to 

 the long selective action of fruit-eating birds. Origin- 

 ally, no doubt, the primitive ancestral vine produced 



