BOTANY: CROCKER AND GROVES 
155 
1. Increase of the acidity of the seed will hasten coagulation of the 
cell proteins. Such a change is known to occur in seeds of certain Rosa- 
ceae, at least if stored in the imbibed condition. 
2. Lepeschkin^ found that in active plant cells a redispersal of cell 
proteins is going on coincidently with coagulation. As a consequence 
at high temperatures where the coagulation was rapid the found and 
calculated Hfe durations agreed closely; while at lower temperatures 
where redispersal is prominent the calculated life durations were much 
shorter than the found values. In the low water content of air dry seeds 
it is possible that the redispersal of proteins is of Httle significance. 
This may limit the method to seeds of relatively low water content. 
3. A sHght error in a and b will give a relatively large error for a life 
duration at low temperatures such as 0° C. At higher temperatures the 
error becomes less. In the data above calculated temperature for a 
life duration of eight years varies little whether a and b are calculated 
by including White's data at 20° C. or merely from the determinations 
above 70° C. 
4. The lower the water content of seeds the more heating they will 
withstand and the greater the longevity at moderate and low tempera- 
tures. This law has its limits, for excessive drying is itself injurious. 
In seeds that will endure dessication injury sets in with a reduction of 
the water much below two per cent, while in forms like Drosera it appears 
before air-dry condition is reached. Our method is, of course limited 
to degrees of dessication less marked than those producing injury. 
5. Undoubtedly longevity under like conditions will vary with differ- 
ent varieties of the same species and even with different crops of the 
same variety; but the general conditions found for a given crop will prob- 
ably apply to other crops of the same variety and to other varieties of 
that species. How far the five points mentioned above will limit the 
appKcation of this method can only be determined by such experiments 
as those outlined above. 
The work shows possibiKties of throwing light on the nature of the 
process of loss of viability in seeds and of leading to a quantitative 
statement of the significance of various storage conditions (especially 
moisture content and temperature) upon the longevity of seeds. 
1 Ewart, Proc. Roy. Soc. Victoria, 2, 1-210 (1908). 
2 Chick and Martin, Amer. J. Physiol, 40, 404 (1910); 43, 1 (1911). 
3 Buglia, Ztschr. Chem. Indust. Kolloide, 5, 291 (1909). 
* White, Proc. Roy. Soc. London, 81 B, 417 (1909). 
^Lepeschkin, Ber. Dtsch. Bot. Gesells., 30, 703-714 (1913). 
