Fig.  i.— Transverse  section  of  Cotton  Root  Bark,  (c)  cork  ;  (cr)  crystals  of 
calcium  oxalate  ;  (b)  bast;  (m)  medullary  rays;  (T)  cells  containing  tannin  ; 
(s)  sieve.    (About  180  diameters. ) 
