Gums, Resins, 



320 



[April, 1909. 



wet I think there is no doubt. I have 

 myself in a little experiment station of 

 my own tried watering some plants and 

 leaving others in the same soil unwater- 

 ed, and the watered plants far out- 

 stripped those unwatered, and seemed 

 to have as much more latex, though 

 the trees are still too young to draw 

 conclusions from as to yield. 



In regard to these three varieties : 

 (1) Manihot Dichotoma. 



The seeds of this variety are much 

 larger than those of the Ceara. Germin- 

 ation takes place in two to three weeks 

 if unfiled, the shell being much softer 

 than in the case of the Ceara. The 

 soil upon which this tree flourishes 

 is variously described as red clay and 

 red loam. The bark of this tree is 

 thinner and more delicate than that of 

 the Ceara, 



(2) and (3) Manihot Heptaphylla 

 and Manihot Piauhyensis. 



The seeds of these two varieties can 

 hardly be distinguished from each 

 other ; they are only a little larger than 

 Ceara seeds. They do not germinate 

 nearly as well as in the case of the 

 Manihot dichotoma. These two varie- 

 ties in the region around Bahia thrive 

 in a sandy soil, growing largely on 

 sandstone mountains. Both varieties 

 do not grow as tall and are smaller 

 than the Manihot dichotoma and in- 

 clined to branch low. They are not 

 affected by the wind so much as Ceara, 

 probably on account of being smaller 

 and more low lying. This also affects 

 the methods of tapping as explained 

 later. The foliage is characteristically 

 green and fresh-looking. 



Methods oj Planting.— There are a 

 number of plantations around Bahia, 

 some of which are now three or four 

 years old. They are planted for the 

 most part 1,000 trees to the acre. This 

 close planting has been adopted because 

 the trees are planted in a dry locality, 

 and it is claimed that if not planted so 

 closely, or say 200 to the acre, the 

 ground would be baked so hard and dry 

 that the trees would dwindle and die. 

 Also the trees are considerably smaller 

 than other varieties, and consequently 

 need less room. 



Methods of Tapping.— In the case of 

 the Manihot dichotoma the bark of the 

 trunk is tapped and an instrument curv- 

 ed at the tip is used. The herring bone 

 or a single cut is used, Cups are used to 

 receive the latex. The latex coagulates 

 quickly on exposure to air but appar- 

 ently not too quickly to prevent its 

 flowing down into the cup's well. Water 

 is sometimes used in the cups to prevent 

 too rapid coagulation. 



In the case of the Manihot piauhyensis 

 and Manihot heptaphylla, the shorter 

 trunk and somewhat thinner bark than 

 the Manihot dichotoma are not suitable 

 for cutting, and by this method yield 

 little latex. A little earth, however, is 

 scraped away from the base of the tree, 

 and the top of the taproot is exposed 

 and an incision with a round pointed 

 knife is made at or near the junction of 

 tap root and trunk, and the latex flow- 

 ing into this hole coagulates and is 

 gathered therefrom. Often the col- 

 lectors coat this little hole with clay to 

 keep the rubber cleaner. Cups have 

 been used, but there is some difficulty 

 in getting them into the hole thus 

 made, and the method is little used 

 at present in collecting from the wild 

 trees, but will doubtless be worked on 

 plantations. 



Yield of the Trees.— This is variously 

 stated all the way from 2| to 11 pounds 

 per year. Though of course these state- 

 ments are made in regard to the 

 gathering of the rubber from wild trees, 

 which are more or less ruthlessly tap- 

 ped, and especially in the case of the 

 Manihot dichotoma the wood is thus 

 often injured severely that the tree dies. 

 Also it is probably wet rubber that is 

 spoken of, and also in some of it, espe- 

 cially the Manihot heptaphylla and 

 piauhyensis, there may be considerable 

 dirt. 



Dr. Ule considers that the Manihot 

 dichotoma has the advantage of its 

 caoutchouc fetching a somewhat higher 

 price. On the other hand the amount 

 produced in the other varieties is con- 

 siderably greater according to him, He 

 therefore prefers these latter varieties, 

 which he considers will supplant the 

 Ceara for the dry and less fertile areas 

 where Ceara is cultivated. There is no 

 doubt, however, that all of these var- 

 ieties yield more than the Ceara. 



Amount of Latex collected by one 

 Man in one Day. — This has been vari- 

 ously stated at fiom 1 to 8 or 10 pounds. 

 Taking into consideration the tendency 

 to exaggeration in regard to any new 

 product and misleading methods of 

 figuring, still it is generally conceded 

 that considerably more can be collected 

 in a day from these varieties than from 

 the Ceara. 



Several thousand seeds of the Manihot 

 dichotoma or Jiquie Manicobar were 

 imported by Mr. Jared G. Smith and most 

 ot the rubber plantations have obtain- 

 ed some of the trees. I have planted 

 a few of these seeds. When filed they 

 germinated in a few days and have 

 grown very well, fully as well as the 

 Ceara so far, in spite of the fact that 

 this is the wrong season of the year 



