H. D. WAGGONER 
gain or loss (Fig. i) to or from the initial water content (19 percent) 
of the seeds used. 
These graphs show the striking changes in water content obtained 
by heating radish seeds of 19 percent initial water content by the three 
different methods. (A subsequent experiment will show that the 
gain in weight of the samples heated by method i does not express 
accurately the amount of water absorbed.) The seeds heated directly 
in water increased in weight very rapidly; those heated in the flasks 
decreased in weight for about six minutes and then remained constant 
during the remainder of the heating; those heated in the oven grad- 
ually decreased in weight throughout the entire thirty minute period 
of treatment. At the end of thirty minutes the seeds heated at 95° C. 
were found to have a water content for method i, of 79 percent, 
method 2, 11 percent, and method 3, 3 percent. A similar variation, 
though less extensive, is seen in seeds heated at 80° C. or 65° C. 
respectively (Fig. i). It has been shown that the resistance of seeds 
exposed to high temperatures is inversely proportional to the initial 
water content at the time of heating. The results obtained in the 
above experiments (Fig. i and Table V) are in entire accordance with 
this statement. 
Data are not at hand upon which to base a complete explanation 
of the resistance of radish seeds to high temperatures. Seeds heated 
in air lose water by evaporation which is a cooling process. Moreover, 
air and water differ materially in their ability to transmit heat. Hence 
we cannot say with absolute certainty that we have subjected the 
seeds used in the corresponding tests to exactly the same temperatures 
for the same periods of time. Data from seeds heated at a given tem- 
perature without suffering any change in the water content during 
heating would be desirable. However the results as shown in Table 
V between water- and oven-heated seeds cannot be explained on the 
basis of cooling. These questions together with related ones will 
form the basis for a future investigation. 
The rate of gain or loss in water content of the seeds when treated 
by method i, 2 or 3 is of interest, since, owing to a change in their 
water content, the seeds show a low (Series i) or a high (Senies 3) 
resistance. The rapid absorption of water in the seeds of Series i 
concomitant with the high temperature is responsible for the marked 
injury as indicated in Tables I, H, HI, and V. On the other hand the 
rapid loss of water in the first six minutes of treatment in Series 2 
