Dr. Axel Preyer 27 
and a thin layer of earth. ' The drawbacks of 
‘this process, especially in rainy weather, are 
too obvious to need discussing. Instead of 
using these earth holes, others erect ‘cemented 
pits inside the warehouses, which, after being 
filled, are likewise covered with banana leaves 
and form a great improvement over the holes 
in the ground. Other planters usé casks or 
wooden cases for fermentation; others, again, 
pile the beans in large heaps on the floors 
of the warehouses, covering the heaps first 
with banana leaves and then with bags or 
thick cloths over the leaves.’ The spreading 
out of the beans on tables or trays, or in 
regular layers 10 to 20 cm. high, is a process 
very much to be recommended. These layers 
are covered with banana leaves and cloths, 
after which boards are laid on them. The 
advantage of this method consists in a 
moderate and very uniform heating of the 
whole mass.” ; 
The preparation of cacao on the Bimbia 
Plantation in the Cameroons is described in 
an earlier issue of this Journal (Der Tvropen- 
filanzer, second year, 1898, p. 9). 
E. Friederici says ‘that if the three tank 
method is used, the whole fermentation: takes 
about sixty hours, and the cacao heaps are 
turned about at least twice a day—at noon and 
1 See Dr. Preyer’s illustration of a cacao-sweating 
tank, p. 30. 
