April, 1909,] 



319 



Saps and Exudations. 



doctors are not agreed as to the utility 

 or otherwise of this addition of creosote. 

 Samples of perfectly white rubber pre- 

 pared by this oxydase-destroying process 

 were to be seen on both the Ceylon and 

 Malaya stands, and it will be interesting 

 to hear what the trade has to say about 

 them. Mr. Bamber's main contention is 

 that uniformity in bulk will be secured, 

 and, further, that the colourless rubber 

 will be found of special use in the manu- 

 facture of certain goods— such as teats, 

 for example — the white colour not being 

 affected by the vulcanization. 



With regard to the subsequent wash" 

 ing and rolling processes it is advised 

 after the first rolling to again immerse 

 the rubber sheet in water at 180 J F. to 

 ensure complete destruction of the 

 oxydase and the complete removal of all 

 soluble matters on which bacteria and 

 fungi grow. After this the rubber is 

 allowed to contract naturally in cold 

 water out of contact with the air. 



Mr. Bamber is against the too rapid 

 drying of the rubber, and remarks that 

 the 10 to 15 per cent, of moisture in 

 Brazilian Para is probably an advantage 

 to it. He does not seem to be enamoured 

 of the vacuum drying process, and thinks 

 that the vacuum process if used at all 

 should only come after the natural 

 drying in order to get the rubber quite 

 dry for packing. The best method in 

 his opinion is the use of perfectly dry 

 air which can be obtained easily and 

 economically by a plant of which a 

 working model was shown at the Ceylon 

 stand. It involves the use of a refri- 

 gerating plant and a system of pipes 

 which strike one as decidedly ingenious, 

 and for the purpose to be achieved to be 

 devised on sound scientific lines.— India 

 Rubber World, Vol. XXXIX., No. 1, 

 October, 1808. 



THE NEW MANIHOTS. 



By Dr. C. E. Waterhouse, 



During the last two years and es- 

 pecially this year great interest has been 

 aroused in some new species of Manihot 

 rubber trees which from all accounts are 

 far superior to Manihot glaziovii, and 

 which should be of special interest to the 

 rubber growers of Hawaii, from the fact 

 that the Manihot glaziovii or Ceara rub- 

 ber tree grows and yields so well in 

 Hawaii. Some of the reasons why, if 

 these species do as well as the Ceara, it 

 will be well worth the while of the rubber 

 growers of Hawaii to pay particular 

 attention to these species in future plant- 

 iugs will be forthcoming later in this 

 paper. 



The export of rubber from the State of 

 Bahia has increased more than ten fold 

 within six years, having risen from 

 100 tons in 1900 of very inferior rubber 

 to over 1,100 tons in 1906 of a very 

 superior grade of rubber. This led to 

 an investigation of the sources of this 

 new supply and the discovery that, in- 

 stead of the low grade of Mangebeira as 

 formerly gathered, the supply came 

 mainly from the three new and very 

 valuable varieties : — 



1. Manihot dichotoma or Jequie Mani- 

 coba ; 



2. Manihot heptaphylla or Sao Francis- 

 co Manitoba ; 



3. Manihot piauhyensis or Piauhy 

 Manicoba. 



These varieties were so named by Dr. 

 Ule, so well known as an authority on 

 the classification of different species of 

 rubber trees, and who visited the State 

 of Bahia and neighbouring States in 1900 

 to look into the sources of this supply. 



Until six years aero Manihot glaziovii 

 was considered the only rubber-yielding 

 species of its genus (though there were 82 

 species recorded which will soon be 100 

 when all those discovered are described). 



It was only in the early part of 1906 

 that even the Kew Gardens, the birth- 

 place, so to speak, of the rubber industry 

 of the far East and always on the 

 lookout for new species of rubber, was 

 aware of the existence of rubber- 

 yielding trees closely related to the 

 comonly cultivated Manihot glaziovii. 



All these species, from all accounts, not 

 only yield considerably more latex than 

 the Ceara, but what is of very much more 

 importance to Hawaii is, the amount 

 which one man can collect is much 

 greater (in other words the cost of 

 collection is considerably less). This is a 

 most important item here owing to the 

 high price paid for labour, in fact the 

 point upon which the whole success of 

 the rubber industry in Hawaii hinges. 



A notable fact in this connection, one 

 which will appeal to any one who has 

 had any experience in tapping the Ceara 

 is that in these new varieties, in shedding 

 the bark, longitudinal slits are formed 

 and the membranous bark peels off in 

 more or less verticle rows. This allows 

 its removal much more easily and there- 

 fore cheaply, than is the case with the 

 Ceara. 



These varieties of Manihot, like the 

 Manihot glaziovii or Ceara, have a very 

 dry habitat, However, just as we find 

 here in Hawaii that the Ceara does 

 better in wet localities, so with these 

 varieties the same may be true. That 

 the Ceara does better here where it is 



