108 PROCEEDINGS OF THE ACADEMY OF [Feb., 



exist in springs where the temperature ranges from 45° to 93° C. Roti- 

 fers and Anguillulidse were found in the Carlsbad Springs of Bohemia 

 at a temperature of 44° to 54° ; Cypris balnearia occurred in water 45° 

 to 50.5° and Stratiomys larva at 69° in a hot spring in Colorado. But 

 the experiments of Dallinger are remarkable illustrations of gradual 

 acclimatization. He kept Flagellata in a warm oven for many months. 

 Beginning with a temperature of 15.6° C. he employed the first four 

 months in raising the temperature 5.5°; this, however, was not neces- 

 sary, since the rise to 21° can be made rapidly, but for success in higher 

 temperatures he found it best to proceed slowly from the beginning. 

 When the temperatures had been raised to 23° the organisms began 

 drying, but soon ceased, and after two months the temperature was 

 raised half a degree more and eventually to 25.5°. Here the organisms 

 began to succumb again, but finally after several years of treatment 

 Dallinger succeeded in rearing the organisms in a temperature of 70° C. 

 The same acclimatization to cold may be shown. Thus the swarm 

 spores of a marine alga were liberated when the temperature of the 

 water was between 1.5° and 1.8° C. 



We can exemplify this kind of acclimatization in the higher plants. 

 Our treatment of the twigs from various localities demonstrates that 

 this kind of acclimatization was operative in the past with each tree 

 species. Sweet peas raised in Calcutta from seed imported from Eng- 

 land rarely blossom and never yield seed; plants from French seed 

 flower better, but are still sterile; but those raised from Darjeeling 

 seed (originally imported from England) both flower and seed profusely, 

 according to Wallace. 10 Speaking of the introduction of the Sea Island 

 cotton into the United States, Wight 11 says that (Gossypium barbadense 

 and G. vitifolium) they were with much difficulty introduced into 

 North America owing to the shortness of the summer season. The 

 former (Sea Island), indeed, could not be established until a fortunate 

 occurrence of a very mild winter permitted the roots to live through it 

 and produce an early crop of fresh shoots in the spring. These bore 

 and ripened, the seed of which was found sufficiently hardy to resist 

 the cold of spring and matured a crop of excellent cotton in the course 

 of the succeeding autumn. Indian corn develops local varieties with 

 extreme readiness, but they seldom succeed when transferred even short 

 distances, at least until time enough for acclimatization has elapsed. 

 E. Davenport sent a standard white Illinois corn, ripening in about 



10 Encyclopedia Britannica, article "Acclimatization." 



11 Watt, Sir George: The Wild and Cultivated Cotton Plants of the World, 1907, 

 p. 272. 



