FIBRES 569 



speaking, the number of leaves produced by a sisal plant 

 during its whole lifetime is between 170 and 200 leaves. 

 As soon as the flower-bearing stem becomes visible it 

 should at once be cut down, unless bulbils are desired, 

 since otherwise the leaves surrounding the stem will not 

 yield proper fibre. The old rule was only to cut those 

 leaves which formed an angle of 45 with the ground. 

 This has proved a mistake, especially in the richer class 

 of soils. In such cases, if the leaves forming an angle 

 of more than 45 with the horizontal are not cut, the 

 result would be that the flower-bearing stem would shoot 

 up too soon, and thus the life of the plant would be 

 shortened. 



After the whole sisal culture has been completely 

 harvested it is advisable to let the ground lie fallow for 

 several years. Exhaustion of the soil can also be avoided 

 by cultivating leguminous plants which enrich the nitrate 

 content of the soil. 



The Extraction of Fibre from the Leaves. 



Fibre extracting is performed by various machines, 

 which are worked either by hand or mechanically. The 

 method by which the flesh is removed from the leaves in 

 such machines is that a rotary drum set with beater 

 ledges presses the leaf against a hard edge, thus beating 

 out the flesh whilst the fibres are gripped above. The 

 leaves are inserted by hand in the so-called " raspadores," 

 and automatically in the larger machines, e.g., the " New 

 Corona." In the raspadores each leaf is inserted 

 separately into the machine with its tip foremost, half 

 of the leaf being thus freed from flesh; it is then removed 

 and its other end inserted into the machine. In the 

 "New Corona" one side of the leaf is gripped by the 

 machine and carried sideways towards a drum, which 

 removes the flesh from the other side; then the part 

 freed from flesh is gripped and carried towards a second 

 drum, which removes the flesh from the remainder. The 

 general principle is the 'same in all the different systems 

 of extracting machines ; the difference being that in some 

 the leaves are transported by chains consisting of links 

 of bronze (Finigan machine), or by spiked wheels of 



