Seaweeds and Leaf-green 



to the fact of algae flourishing in such temperatures as 

 these, but at any rate they do live at 52 C. and quite 

 vigorously. 9 



As seeds and spores, vegetable protoplasm is able to 

 support far higher temperatures even than 70 C. Mosses 

 have survived temperatures of 8o° and 90 C. 10 Bacilli 

 have been known to grow at 6o° to 70 C. 11 Seeds of 

 certain flowering plants were not killed by exposure to 

 enormous temperatures such as 90 or 120 C, 12 and a 

 yeast spore revived after 130 C. 13 



Perhaps the endurance of great cold is even more 

 remarkable. 



Those very algae which thrive at 52 C. can with- 

 stand a cold of —12° C. for four hours, and various 

 spores of seaweed were not killed by — 20 to — 30 C. 14 

 Drs. Macfadyen and Rowland found that the spores of 

 some bacteria began to grow again after they had been 

 chilled for ten hours at a temperature of — 252 C. 15 Not 

 only so, but the seeds of several vegetables were kept 

 for 130 hours at temperatures of — 185 to — 192 C. and 

 were not much the worse, germinating quite satis- 

 factorily after this awful and unimaginable cold ! 16 



It is very hard to understand such facts as these. 

 How is it possible that living protoplasm can endure 

 such horrible extremes of temperature which indeed 

 can scarcely ever be produced naturally ? No doubt 

 the protoplasm must be dry and perhaps temporarily 

 lifeless during the process, but then how is it that its 

 delicate complex mechanism is in full working order 

 as soon as the conditions improve ? 



These facts are, however, quite sufficient to assure us 

 that low forms of algae might have been in existence at a 

 very early stage in the earth's history and long before 

 there were snow caps at the North and South Poles. 



It also explains why we find algae luxuriantly flourish- 



34 



