Appendix A 363 



general conclusions from the results of his own obser- 

 vations and from the recorded studies of other men ; and 

 there is nothing more needed at the present moment 

 among our scientific men than the development of a school 

 .of men who, while industrious and minute observers and 

 collectors and cautious generalizers, yet do not permit 

 the faculty of wise generalization to be atrophied by ex- 

 cessive devotion to labyrinthine detail. 



Haseman upholds with strong reasoning the theory 

 that since the appearance of all but the lowest forms of 

 life on this globe there have always been three great con- 

 tinental masses, sometimes solid sometimes broken, ex- 

 tending southward from the northern hemisphere, and 

 from time to time connected in the north, but not in the 

 middle regions or the south since the carboniferous epoch. 

 He holds that life has been intermittently distributed 

 southward along these continentEil masses when there 

 were no breaks in their southward connection, and inter- 

 mittently exchanged between them when they were con- 

 nected in the north; and he also upholds the view that 

 from a common ancestral form the same species has 

 been often developed in entirely disconnected localities 

 when in these localities the conditions of environment 

 were the same. 



The opposite view is that there have been frequent 

 connections between the great land masses, alike in the 

 tropics, in the south temperate zone, and in the antarctic 

 region. The upholders of this theory base it almost ex- 

 clusively on the distribution of living and fossil forms 

 of life ; that is, it is based almost exclusively on biological 

 and not geological considerations. Unquestionably, the 



