The coagulum, about 3 cm. thick, is placed on a board 
and rolled by hand to a sheet about 6 mm. thick, then 
washed in a basin with water and hung in the shade to 
dry. Home made rolling machines which resemble 
wringers with wooden rollers are used in many places to 
produce sheets of uniform thickness. 'To corrugate or to 
smoke the sheets is inadvisable in Ceara because prepared 
mangabeira rubber deteriorates rapidly, especially when 
nearly dry and exposed to the air. 
There are better methods for the preparation of man- 
gabeira rubber, yet none is as satisfactory for field use. 
By the use of exact quantities of expensive chemicals 
and careful heating it is possible to produce a mangabeira 
rubber which approaches Hevea in quality. However, 
the native tappers lack the skill and the careful habits 
necessary to accomplish this, and it was even difficult to 
introduce the simple scheme outlined above. 
Maninor 
Manihot is a large genus with its center of distribution 
from Ceara to central Baia, Brazil. It is best known to 
Americans in the form of tapioca which is obtained from 
Manihot esculenta Crantz, a species native to Brazil, 
and like Hevea, extensively grown in the East Indies. 
As in the genus Hancornia many species have been de- 
scribed, but the paucity of specimens in herbaria, the 
scanty material upon which many species were based, 
and the difficulties encountered in the field in ascribing 
many of the variable trees to a definite species suggest 
that a monograph of the genus based upon field study 
in this part of Brazil is needed. 
Manihot Glaziovii Muell.-Arg., the large rubber yield- 
ing species which has been tried on plantations in Africa 
and the East but replaced by Hevea, is native to the 
Serras of Baturité and Maranguape, Ceara. Most of the 
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