For practical purposes it is often convenient to consider the cane as composed of juice and fiber, leaving out of mind the composition of these two component parts. Proceeding on these lines, we may say that the amount of juice in a given volume of cane will be the greater, the less the amount of fiber. The fiber of the cane-stalk exists in the form of strands or fibrovascular bundles distributed in the stalks as follows : (1) A part in the form of fine parallel fibers in the internodes, and (2) a part woven together at the nodes. From this it follows that a cane having numerous nodes close together, so that the internodes are short, contains the great est amount of fiber, because it is at the nodes or joints that the fiber is most compact, and the sugar bearing tissue is at its minimum. Cane with long joints is therefore generally looked on with favor by planters as being likely, other things equal, to con tain the greatest amount of sucrose. It frequently happens when the growth of the cane is hindered by cold weather or by drought, that the slower growth is marked by an abundance of joints or nodes near together. Such cane is usually charac terized by a lower percentage of sugar. The prac tical application of this fact is illustrated by all those methods of culture that tend to keep the cane growing uniformly, as, for example, in the appli cation of irrigation water to piece out the irregu larity of the natural rainfall, and the application of artificial manures to stimulate the growth dur ing periods when the growth would naturally be slow.
In general it may be said that the varieties that are lowest in fiber are such as give the highest yield of sucrose and are the varieties preferred where the conditions are suitable for them. They are, however, what may be termed delicate canes, and it frequently happens that through the attacks of diseases they are made unproductive, so that in time they have often been replaced by other varieties with more fiber, but more resistant to disease. Examples of this are the Bourbon cane of the West Indies, the Lahaina cane of Hawaii, and the Rappoe cane of Australia. When, however, these canes meet with the right conditions, they are still preferred to any others. With strong sunlight, fertile soils, high tempera ture and uniform conditions, all of which favor the growth of the cane and are not particularly favorable to fungous pests, these canes are the most profitable. Good cane, as it comes to the mill in most tropical countries, contains up to and sometimes even beyond 20 per cent of sucrose, averaging 15 to 18 per cent. The extracted juice contains, under favorable conditions, 17 to 18 per cent of sugar.
It will have been noted that the amount of extractable sugar depends on its own nature and that of the collateral products, and not altogether on the structure of the stalk. Modern mills are so
powerful and modern methods so efficient that the sugar extracted has reached as high as 97 per cent of the total sugar content, so that the abso lute limit has been very nearly reached. The economic limit has even been much more nearly reached, since the extraction of the last traces of sugar would be too costly to render it practicable. The average of good mills is not far below 95 per cent.
The importance to the planter of understanding the distribution of the sucrose in the stalk is also shown by the bearing this distribution has on the matter of harvesting. Cutting close to the ground results in saving more sugar, and it frequently happens that attention to this matter results in a material increase in the profits at a cost small in proportion to the gain. So, too, it sometimes happens that in certain soils and under certain conditions, when the land afterward is to be plowed and re planted, it is profitable to pull the stalks, in spite of the fact that the operation is more expensive than cutting. These details of the management are de pendent on the fact that the lower part of the stalk contains considerable amounts of sucrose. Again, it sometimes happens that the planting and the har vesting can go on simultaneously for months at a time. Under such conditions it is possible to secure seed-cane for the new planting from the tops of the cane that is being harvested. Now the tops, above a certain point that has accurately to be deter mined, contain comparatively little extractable sucrose. The point at which to cut off the top for seed purposes therefore becomes an important matter, especially as it is precisely the parts that contain the less amount of sugar that are particu larly good for seed. By cutting the tops too low, tons of sugar may be lost without any correspond ing gain to the seed.
(2) Structure of the stalk.—The nature and dis tribution of the fiber in the stalk determine the resistance of the cane to various adverse influences, so that these qualities become of great importance. If, owing to the nature of the fiber, the stalk is brittle, this fact will cause the cane to break more easily during wind-storms, so that for windy locations canes of this character are unsuitable. The toughness of the stalk is also related to the access of certain pests. Strong fibrous varieties are more resistant to certain insect borers than are the varieties with less fiber, so that, although the latter may be higher in sucrose, it is some times more profitable to grow the former. Where the attacks of these pests are severe, the actual yield and the profits may he greater with the poorer variety, owing to the fact that the ravages of the pests are less.