THE KEEPING QUALITY OF CRANBERRIES. 5 
picked berries show better keeping quality than those picked early. 
The greater injury to the light-colored early-picked berries is appar- 
ently due to the higher respiration rate of these berries. 
TEMPERATURE OF THE WATER. 
The effect of temperature is very important in determining the rate 
of respiration. Morse (8) has recently proved that in the cranberry, 
as in many other fruits (7), the rate of respiration is twice as rapid 
at 10° as at 1° C. and that the rate doubles again at 20° C. This 
means that the amount of oxygen necessary to maintain the normal 
activity of the berries is twice as great at 10° and four times as great 
at 20° as at 1° C. On the other hand, the capacity of water for 
holding oxygen diminishes with the rise of temperature. Other 
things being equal, then, the colder the water the better it is for use 
in water-raking. It is obvious that in this respect the conditions 
are more favorable for continued flooding in Wisconsin than in 
Massachusetts or New Jersey. 
OXYGEN CONTENT OF THE WATER. 
The importance of the flooding water in the cranberry industry 
has led to a careful study of different water supplies and their relation 
to injury from flooding by one of the writers (Bergman). These 
studies, which are in part unpublished, indicate that a very important 
factor, perhaps the most important factor in water injury, is the 
oxygen content of the water. Water having a high oxygen content 
will cause much less injury in a given time than that having a low 
oxygen content. The oxygen content of flooding water under 
natural conditions is determined by atmospheric pressure, tempera- 
ture, the quantity of organic matter in the water and substratum, 
and the light intensity. 
As atmospheric pressure varies only slightly from day to day, this 
factor may for practical purposes be disregarded. The temperature 
influences both the capacity of the water to hold oxygen and the rate 
at which the oxygen is taken up from the water by organic matter. 
Water reaches its greatest capacity for oxygen at 0°C. This capacity 
decreases with the rise of temperature. On the other hand, the rate 
of oxidation of organic matter increases with the rise of temperature. 
From both points of view, then, the cooler the water the more favor- 
able for a high oxygen content. 
The presence of decaying organic matter in the water or in the 
substratum reduces the oxygen content of the water. Decay is a 
process of oxidation, and decaying organic matter in the water or the 
substratum can obtain oxygen only from the water. Therefore, it 
decreases the oxygen content of the water in proportion to the 
amount of organic matter present and the rate of oxidation, which, 
in turn, depends on the temperature. 
