30 ELECTRICAL STRUCTURE AND 



The edible seed, on the other hand, must, if it is to be 

 useful as a food, have keeping qualities, be able to preserve 



We(5ativc terminal 



a, _ . 



Outer insulation 



Fig. 28. SECTION OF EDIBLE CHESTNUT. [Original photo.] 



a, a, a, a, a positively charged white, pithy substance ; 6, inner 

 insulating membrane ; c = conducting layer ; d = outer insul iting 

 membrane ; e seed substance ; j = beneath this is the tongue-like 

 projection ; i = cavity in which the seed substance is ensconced. 



itself unimpaired for a considerable period of time, and in 

 this we may find a reason for the quantity of moisture with 

 which it is, under considerable pressure, charged. But 



Fig. 29. SECTION OF EDIBLE CHESTNUT : THE OTHER HALF. 



[Original photo.] 



The seed substance seen in the central cavity is not attached in any 

 way to it. Before division of the pod it formed, of course, part of the 

 seed substance shown in Fig. 28. 



it is also a seed, and when it is planted in the soil and the 

 outer membrane or some portion of it becomes a 



