SKETCH OF OSWALD HEER. 553 



past ages diffused simultaneously through both continents, indications 

 of ancient territorial connections. The substitution of the hypothesis 

 of a common origin of life at the poles and its diffusion by migrations 

 to the southward over all the continents, for the theory of Atlantis, 

 which he had expounded in his earlier works, was of gradual growth, 

 and was the direct result of his examinations of the Arctic fossil flora. 

 In this he was struck by the abundance of the species of a southern 

 and even tropical character, which he found in beds reaching far up 

 toward the extreme north. On the evidence of such fossils was built 

 the theory of a warm, moist climate prevailing in the Arctic as well as 

 in the temperate and sub-tropical regions during the Tertiary period, 

 which, suggested by Heer, has been and elaborated by De Saporta, and 

 is avowed by Dr. Gray. 



Heer never accepted the Darwinian theory of the origin of species 

 by variation and natural selection. To it he objected, in general, that 

 no new species had arisen within human knowledge ; that no transi- 

 tional forms had been discovered anywhere ; and that it was inconsist- 

 ent with the progress from simpler to more highly organized beings 

 which he conceived to be the rule of development. To account for the 

 changes that had evidently taken place during geological history, 

 he supposed that, at certain undetermined epochs, species underwent 

 changes, the completion of which occupied only a relatively short 

 time, to be again consolidated and continue unchangeable till the 

 moment when another crisis should bring on a new recasting. 



The delicate health which marked his life during the period in 

 which he was best known to science prevented Heer's making ex- 

 tensive explorations in person. Most of his time was spent in his 

 study, examining the collections submitted to him by stronger and 

 more active men, and more capable of enduring the fatigues of such 

 works. But it is to him, M. de Saporta remarks, that we are indebted 

 for our knowledge of the meaning of what such men discovered. 

 Without him, active to his last hour, it would have taken a very long 

 time for phytologists, in the absence of any concert of understanding, 

 to accomplish the summarizing of their aggregate work which he did 

 so successfully, and with so much clearness and intelligence. He was a 

 sufferer from pulmonary disease, and during the last twelve years of 

 his life did much of his work in bed, having his papers and specimens 

 arranged upon a table before him, while his daughter acted as his 

 scribe. Having finished the last volume of his " Fossil Arctic Flora " 

 in the summer of 1883, he was taken to a sheltered retreat on Lake 

 Geneva, for the recovery of his exhausted strength ; and he died at his 

 brother's house. It is said of him by his biographer in " Science," 

 and repeated by Dr. Gray, that " a man more lovable, more sympa- 

 thetic, and a life more laborious and pure, one could scarcely imagine." 



