Heat and Organization. 167 



Tyndall says, " ever weighed the perfume of a rose," but the 

 perfume of the rose absorbs radiaut heat with 30| times the 

 power of the air, and that of aniseed with 372 times the air 

 power. " It would be idle," adds Prof. Tyndall, " to specu- 

 late on the quantities of matter implicated in these results. 

 Probably they would have to be multiplied by millions to bring 

 them up to the tension of ordinary air." Thus — 



" The sweet south, 

 That breathes upon a bank of violets, 

 Stealing and giving odour," 



owes its sweetness to an agent which, though almost infinitely 

 attenuated, may be more potent as an interceptor of terrestrial 

 radiation than the entire atmosphere from bank to sky.* 



In the present state of investigation it is impossible to 

 state the precise limits of heat and cold, beyond which all 

 living organisms are destroyed. On Alpine snows the Proto- 

 coccus, a simple confervoid plant, forms red patches, and grows 

 in spite of the cold, while other members of the same family 

 rejoice in warm situations. If we pass from low to high tem- 

 peratures, we meet with some curious examples of vegetable 

 life nourishing afc a heat we might have fancied fatal to its 

 existence. " In the hot springs near a river of Louisiana," 

 for instance, " of the temperature of from 122° to 145°, there 

 have been seen to grow, not merely Confervse and other her- 

 baceous plants, but shrubs and trees ; and a hot spring in the 

 Manilla islands, which raises the thermometer to 187°, has 

 plants flourishing in it and on its borders. A species of Chara 

 has been found growing and reproducing itself in one of the 

 hot springs of Iceland, which boiled an egg in four minutes ; 

 various Confervas, etc., have been observed in the boiling springs 

 of Arabia and the Cape of Good Hope ; and at the island of 

 New Amsterdam there is a mud spring which, though hotter 

 than boiling water, gives birth to a species of liverwort. "f 



Dry spores of Uredo, according to Hoffmann, are not killed 

 by a heat of 128° C. ; but the experiments of Julius Sachs on 

 the highest temperature that vegetation can sustain, throw 

 much doubt on the extreme statements of certain other ob- 

 servers. M. Sachs found that in the space of ten to twenty 

 minutes, a temperature of 51° C. in the air, killed the most 

 diverse kinds of plants, and 45° to 46° C. in water sufficed to 

 cause death. J It does not however follow that because plants 

 that had been growing at lower temperatures were killed by 

 such an augmentation of heat as he describes, that similar plants 



* Tyndall, p. 360. 



t Carpenter's Manual of Physiology, p. 63, 3rd edit. 



X Flora, Jan. and Feb. 1861 ; Archives des Sciences, July, 1864, 



