1!) 



Saps and Exudations. 



plantation, and for this reason some people have claimed that shade-grown trees 

 yield more. I believe that the reason temperatvire affects the flow is because a 

 large amount of the water is evaporated, and the latex is more solid and does not 

 flow so freely. 



COLLECTING CUPS. 



In gathering the latex the first consideration is the cups. The cups now used 

 are made of sheet-tin cut to the right shape, bent round, and soldered on one edge. 

 The side which goes against the tree is cut in a curve which can be made to fit any- 

 sized tree by slightly changing the angle against the tree. On each side of the 

 curve is a pin which is driven into the tree to hold it. These cups are cone shaped, 

 and on this account poor, as the latex coagulates in the point, and is hard to wash 

 out. A round base would be an improvement. A second improvement would be 

 to do away with the pins, make the cup of somewhat stiffer materril, sharpen the 

 curved edge, and fasten it to the tree by pushing the edge under the bark. This 

 leaves no space between cup and tree for the latex to run through. The cups now 

 employed can be used this way when the pins come off, as they frequently do, and 

 if they were somewhat stiffer would be all right in that respect. The cups now 

 in use are rather small. Their capacity is about sixty cc, or half a gill. 

 A cup with a capacity of one gill should be sufficient for trees up to nine or 

 ten years old unless the yield increases unexpectedly. 



Collecting the Scrap.— Gathering of latex consists not only of taking 

 what runs into the cup, but also what remains on the tree. The first latex to flow is 

 rather watery, and runs into the cups. This flows only a short time, giving nearly 

 a cupful with the best-yielding six-years-old trees sometimes giving more at the base 

 of the tree. This latex flows slowly and for some time, but has ceased in about fifteen 

 minutes after tapping. This latex can be removed with a spoon or with the fingers. 

 A small amount is always left in the cut which cannot be removed as latex, and 

 when coagulated there is too little of it to be worth removing. The only way to get 

 this latex is not to do any spooning, but to allow the latex to coagulate in the cuts 

 and remove it in a few days. Rubber coagulated in this w r ay is very clean it the 

 trees have not too much moss on them. The objection to this is that if a heavy rain 

 comes before the latex is coagulated it is all lost. It might be a good plan to gather 

 in this manner in the dryer times. 



THE MANIPULATION OF THE LATEX OP CASTILLOA. 



Washing. —When the latex is brought in from the field it contains small 

 pieces of bark and moss (also mud in the single incision method) which must be got 

 rid of. The bark and moss can be strained away. A certain amount of the bark, 

 however, is very small and will go through a fine sieve. This bark can be taken out 

 by straining through cheese-cloth, but the cloth does not last long and often breaks 

 through the straining. Practically all the fine bark can be removed in the washing, 

 and so it is not necessary to strain it out. It is hard to strain pure latex, and 

 generally water must be added to it first. It can be strained pure by working it 

 through the sieve with the fingers, but this breaks up the bark, and much more goes 

 through than ordinarily would do so. It might prove desirable not to add any water 

 to the latex during its manipulation, as a small amount of latex is unavoidably lost 

 by washing, but this would not make much difference in only one washing. 



Washing when mud is in the latex and when it is not are two different 

 things. The globules of rubber will not rise to the top nearly as quickly when mud 

 is in it as when there is no mud. The first washing takes two or three hours with 

 mud, and about fifteen minutes without. In either case a black water forms and 

 must be run off. There seems to be no limit to the number of times which the latex 

 can be washed and still give a dark-coloured water, but there is a limit to the rising 



