18 
also found to contain a small amount of starch adhering to the chloro- 
plastids. The deeper- lying tissues rarely contain any starch ; neither 
was dextrin detected in more than mere traces; and from the results 
of acid hydrolysis we may conclude that the green fruit contains no 
substance of importance that is capable of giving rise to sugars during 
subsequent ripening. 
The chief carbohydrates produced in the plant, then, may be con- 
sidered to be of the nature of sugars and starch, and these may be" 
looked upon as being produced somewhat as follows : The protoplasm 
transforms carbon dioxid and water into sugars by the intervention 
of chlorophyll, just as is done in all plants. The excessive accumula- 
tion of sugar in the chlorophyll-bearing cells is prevented by its 
transformation into starch, which, in turn, is stored principally in 
the stalk. During the vegetative growth of the fruit relatively small 
amounts of carbohydrates are transferred to it, but in the normal 
ripening process there is an enormous accumulation of sugars in the 
fruit, which sugars are derived from the carbohydrates previously 
stored as starch in the stem. 
Normally, pineapples stand almost perpendicular and are some- 
what protected from the direct rays of the sun by the crown. Occa- 
sionally there are to be observed in the fields pineapples that have 
weak steins, which results in the fruit becoming turned over and 
exposing one side to the direct rays of the sun. The pineapples 
that are thus exposed become blanched on the upper side, which ap- 
pears to mature earlier than the lower and more protected surface. 
Such pineapples also are less palatable in the upper and exposed 
portion. 
With a view of determining the composition of such fruits a num- 
ber of analyses have been made. These pineapples were sampled in 
such way as to secure one portion from the upper side and one from 
the lower side. Partial analyses of these portions are recorded as 
follows : 
The composition of upper and lower portions of pineapples. 
Serial 
No. 
Acidity 
asH 2 S0 4 . 
Reducing 
sugars 
calculated 
as invert 
sugar. 
Sucrose. 
Total 
sugars. 
Polarization. 
Direct. 
Invert. 
Tempera- 
ture. 
119 
Per cent. 
0.51 
.51 
.40 
.74 
.88 
.98 
.72 
.55 
.63 
.69 
Per cent. 
3.06 
4.35 
4.00 
3.44 
3.33 
2.98 
4.17 
4.54 
3.64 
3.83 
Per cent. 
5.58 
8.42 
4.81 
6.17 
6.78 
8.41 
7.48 
8.45 
6.16 
7.86 
Per cent. 
8.64 
12.77 
8.81 
9.61 
10.11 
11.39 
11.65 
12.99 
9.80 
11.69 
4.1 
6.4 
3.4 
4.7 
4.9 
6.4 
5.6 
6.3 
°V. 
-3.0 
-4.3 
-2.8 
-3.1 
-3.7 
-4.3 
-4.0 
-4.5 
°C. 
31.0 
119 
31.4 
120 
31.7 
120 
32.5 
121 
31.7 
121 
30.8 
122 
28.6 
122 
Lcwer side 
29.7 
Average, upper side. . . 
Average, lower side . . . 
[Bull. 28] 
