1922] EVANS—GERMINATION 225 
completely removed by treatment with H,SO, or abrasion with 
sand, as for instance 11.75 to 1.33 for Washington seeds untreated, 
and 5.77 to 1.37 for these seeds when treated with H,SO, for 
three minutes. 
3. In after-ripened seeds with coats untreated, the restricting 
effect of the coats shows particularly at low temperatures 8°—10° and 
11.6°, and again at high temperatures, 42° for Washington seeds, 
and 46.1° for Indiana seeds. In both cases these effects can be 
lessened by treating the coats with H,SO, or abrading them with 
sand. 
Acknowledgment is due Dr. W1tt1AM Crocker for suggesting 
this problem, and guiding the work. 
Mississippt STATE COLLEGE FOR WOMEN 
CoLumBus, Miss. 
LITERATURE CITED 
1. Batts, W. L., Temperature and growth. Ann. Botany 22:557-591!. 
1908. 
2. BEAL, W. J., Vitality of seeds buried in the soil. Ambherst., Mass. 
3- CROCKER, W., Mechanics of dormancy in seeds. Amer. Sons, Bot. 
3299-120. 1916. 
4. CROCKER W., and Davis, W. E. (unpublished work). 
- Eckerson, Sopuia H., A physiological and chemical study of after- 
ripening. Bor. Gaz. 55:286—-209. 1913. 
Kanirz, A., Temperatur und Levens Vorgange. Gebriider Borntraeger. 
Berlin. rors. 
7- LEHENBAUER, P. A., Growth of maize stediings | in relation to temperature. 
Physiol. Hoscsches 43447. 
8. Lerrcu,-I., Some experiments on the influence of temperature on rate of 
growth in Pisin sativum. Ann. Botany 30:25-46. 1916. 
SHULL, C. A., Oxygen pressure and the germination of Xanthium seeds. 
Bor. Gaz. 48: 387-390. 1909. 
- Switu, A. M., On the application of. the theory of limiting factors to 
measurements and observation of growth in Ceylon. Ann. Roy a 
Gard. Peradeniya 3:303-375. pls. 22-25. 1907. 
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