MEMORANDA. ; 61 
tween the atmosphere and the air passages in the lower layer 
of parenchyma, through the denser tissue which lies over it, 
the more usual communication, by stomata opening immedi- 
ately into the cavaties of the spongy parenchyma, being pre- 
vented by the submersion of that side of the leaf on which it 
is situated.—Grorce Oattvisr, M.D., Lecturer on Institutes 
of Medicine and Histology, Marischal College and University, 
Aberdeen. 
