16 
growing at the expense of the fruit. Experiments in removing the 
crown from young fruits indicate that the core is thereby rendered 
smaller and that the fruit is larger in cross diameter at the top, as- 
suming a more cylindrical shape. The facts which have been stated 
regarding the distribution of starch in the pineapple plant and 
therefore of the possible sources of sugar in the ripening of pine- 
apple fruits are in harmony with the findings of Hume and Miller, 1 
that the sugar content is higher at the base of the fruit than in the 
crown and higher nearer the core than at the surface. This would 
indicate that the sugar enters the fruit through the fruit stem at the 
base. 
While pineapples in ripening after removal from the plant do not 
develop any higher sugar content than they had at the time of re- 
moval, they nevertheless undergo all the other processes which are 
characteristic of ripening. The color changes are the same as those in 
fruits which ripen on the plant and the fruit becomes soft and juicy. 
It is a matter of common knowledge that only a small amount of 
juice runs out of the cut surface of a green pineapple while much 
larger quantities escape from similar cuts from ripe pineapples. This 
is at least partly explained by reference to D and E of Plate II. In 
D is seen a cell from the soft pulp of a completely ripened pineapple. 
The cell wall is thin, delicate, and is easily torn. In fact the walls 
here and there in ripe fruits are completely broken down in the 
ripening process so that some of the larger cavities may be parts of 
what was previously several cells. In the green fruits, on the other 
hand, as shown in E, Plate II, the cell walls of the pulp tissue of the 
fruit are much thicker. The thickening of these cell walls is com-" 
posed of irregular masses of a collagenous nature. During the ripen- 
ing process this material appears to be dissolved, leaving the thin cell 
wall of the delicate tissue which is characteristic of the pulp of ripe 
fruit. 
THE CHEMISTRY OF RIPENING. 
The physiology of the pineapple plant indicates some peculiarities 
belonging to this plant, and which are different from those of most, 
fruits. The chemical changes taking place during ripening have 
previously received some attention at this station, 2 and in order to 
have a more strict chemical basis for the interpretation of the physi- 
ology already outlined, it is thought that a further discussion of these 
data will be of interest. It has been shown that the average composi- 
tion of the green fruit, just before the beginning of the ripening 
process, is as follows : Acidity, as sulphuric acid, 0.39 per cent ; fiber, 
1 Florida Sta. Bui. 70. 
2 IIaw;iii Sta. Rpt. 1910, pp. 45-50; Jour. Indus, and Engin. Chem., 3 (1911), pp. 
403-40.1. 
[Bull. 28] 
