HAIRS AND EMERGENCES 147 



traced in the Rose, or in species of Rubus, by cutting transverse 

 sections of the young stems and petioles on which the prickles are 

 inserted, and selecting those sections which traverse the young 

 emergences : the sections may be cleared with " eau de javelle " : 

 it may readily be demonstrated in these that the prickles arise not 

 from the epidermis only, but also from the subjacent tissue of 

 the cortex. 



L 2 



