FRUITS AND NUTS 97 



isfactory results. In fields of growing pineapples the sticks of 

 dynamite are exploded about 20 feet apart both ways at a 

 depth of about 4 feet. This operation, if properly carried out, 

 does not disturb the surface layer of soil and therefore does 

 not interfere with the growth of the plants. 



It has been found by practical experience and by scientific 

 investigation that pineapples will not endure an excess of either 

 lime or manganese in the soil. The effect of an excess of lime 

 is to produce a yellowing of the leaves and the development 

 of small fruits in which the normal color does not appear. 

 Manganese, if present in the soil to an extent of more than 3 

 per cent., has similar effects, but the effects are usually mani- 

 fested to a much greater degree. On highly manganiferous soil 

 the pineapple leaves turn yellow and the young fruit develops 

 a decided pink color long before it has reached its full size 

 and, of course, far in advance of the process of ripening. 

 These fruits even when ripe are extremely acid and unpala- 

 able. Manganese when present in the soil in excess has the 

 effect of forcing the pineapple plant to absorb undue quantities 

 of lime. Some of this lime is thrown out of solution in the 

 form of needle-like crystals of oxalate of lime. The pineapple 

 leaf apparently has no breathing pores or stomata, at least 

 thorough search has failed to detect any stomata. The chloro- 

 phyll of the pineapple leaf is largely located on the under side 

 of the leaf and is protected from the direct rays of the sun by 

 a reddish-colored sap in the epidermis of the upper side of the 

 leaf and by a thick layer of water-distributing tissue above the 

 chlorophyll. 



The fruit of the pineapple differs in its composition and rip- 

 ening process from the banana or apple or pear. At no stage 

 of growth, however small or green, does the pineapple contain 

 any considerable quantity of starch. In fact, there is no meas- 

 urable quantity of starch in the pineapple at any time except 

 a few small granules in the green tissue of the rind immediately 

 under the eyes of the fruit. As already indicated, however, 



