THE WORK OF FRUITS 317 



How does this reach them? A squash or a pumpkin 

 is a favorable object for study : it may take up as 

 much as a pound and a half of water in twenty -four 

 hours. Cut a young growing squash from the vine 

 and place the cut end in eosin solution, and allow it 

 to stand for several days. Trace the eosin up through 

 the bundles to the seeds. Do you find a bundle reach- 

 ing to each seed ? Does the bundle grow larger as the 

 seed develops? Does the fruit lose water by transpi- 

 ration? Test this matter in the fashion already 

 described for leaves. Do you find any stomata in the 

 epidermis of the fruit (examine microscopically and 

 also test in the air-pump). Grapes are of especial 

 interest in this connection : examine also apples, 

 pears, etc. Admirable means of protection against 

 transpiration are found in the thick, woody walls of 

 nuts, drupes (Peach, Eucalyptus, etc.). 



Does the fruit need a supply of air? Repeat the 

 experiment shown in Fig. 31, using immature fruits 

 instead of seeds. Try the effect of smearing over 

 young fruits completely with vaseline : does it retard 

 their development? Do they contain much air in 

 their tissues ? Place some of the tissue (preferably a 

 piece of watermelon flesh) under water in the air- 

 pump, and exhaust. 



How does the air travel through the stalk, etc., to 

 the fruit? Investigate by the methods previously 

 described. 



