OSWALD HEER AND ARCTIC FLORA. 657 



intimately allied with his later life here as with 

 its earlier European portion. 



His own health, which had seemed for a 

 time to have regained the vigor of youth,, 

 broke down again in the following spring, and 

 an attack about the region of the heart dis- 

 abled him for a number of weeks. To this 

 date belongs a short correspondence between 

 Agassiz and Oswald Heer. Heer's work on 

 the Fossil Flora of the Arctics had recently 

 appeared, and a presentation copy from him 

 reached Agassiz as he was slowly regaining 

 strength after his illness, although still con- 

 fined to the house. It could not have come at 

 a happier moment, for it engrossed him com- 

 pletely, and turned his thoughts away from 

 the occupations which he was not yet allowed 

 to resume. The book had a twofold inter- 

 est for him: although in another branch of 

 science, it was akin to his own earlier investi- 

 gations, inasmuch as it reconstructed the once 

 rich flora of the polar regions as he himself 

 had reconstructed the fauna of past geological 

 times ; it clothed their frozen fields with for- 

 ests as he had sheeted now fertile lands with 

 ice. In short, it appealed powerfully to the 

 imagination, and no child in the tedious hours 

 of convalescence was ever more beguiled by a 



42 



