Notes . 
459 
cambium, diseased groups of ceils, including laticiferous vessels, become enclosed in 
a ‘ pocket ’ of stone cells. The number of meristematic zones will depend on the 
number of rows of laticiferous vessels affected and their disposition in the bark. 
According to the evidence collected by Bateson, Sanderson and Sutcliffe (Malaya); 
Rands and Bobilioff (Java), the brown bast disease is attributable to physiological causes. 
Keuchenius , 1 who has isolated bacteria from the bark of trees affected with brown 
bast, has not succeeded in causing the disease as a result of inoculating healthy trees 
with the organism obtained. Owing to the occurrence of widely distributed sieve- 
tube degeneration in the tissues affected with incipient brown bast, the disease is 
analogous to the cases of phloem necrosis described for the potato by Quanjer 2 3 
and for Liberian coffee by Stakel . 8 The special anatomical features described 
by Sanderson and Sutcliffe would appear to be a secondary development. 
ARTHUR S. HORNE. 
Department of Plant Physiology and Pathology, 
Imperial College of Science and Technology. 
1 Keuchenius, P. E. : Onderzoekingen over bruine bastziekte. Archief voor de Rubbercultuur 
in Ned. Indie, 1920, Feb., Jaarg. iv, p. 1. 
2 Quanjer, H. M. : Die Nekrose des Phloems der Kartoffelpflanze als Ursache der Blattroll- 
krankheit. Mededeelingen, Rijks Hooge Land-, Tuin- en Boschbouwschool, Deel vi, 1913. 
3 Stakel : Phloemnecrose of Liberian Coffee. Buli. Dept, van de Landbouw in Surinam. 
