1885.] NATURAL SCIENCES OF PHILADELPHIA. 31 



as elsewhere, he had given illustrations of the sudden appearance 

 of identical forms in widely separated localities. If we may gene- 

 ralize from these facts, as we seemed almost warranted in doing, 

 we need not be always looking for the links supposed to be missing, 

 which the belief in the hypothesis of development by slow modi- 

 fications compelled us to search for, nor need we be reduced to 

 the only alternative of believing that all new species sprang 

 from one parent, which formed a centre of distribution in each 

 particular case. A whole species might be called into existence 

 in the shape of hundreds of individuals or in numerous centres, 

 if only a law that we know from these instances can operate 

 suddenby and exceptionally should continue regularly to act. 

 Such a belief would tend materially to remove difficulties in the 

 way of theories of evolution, that now prevented a full accept- 

 ance thereof. 1 



If we can conceive that a suddenly introduced and yet perma- 

 nently acting force was introduced to operate on some lower 

 beings, the difficulty might be removed. It seemed to him that in 

 some palaeontological fields there are evidences of rapid evolution 

 at certain periods, and of greater permanency at others, and this 

 could only be by the introduction of a force equal to the eruer- 

 genc3 r , as in this sudden case brought to the notice of the 

 Academy above. 



It would be an interesting study to endeavor to trace the laws 

 that operated in these changes. In this study we must leave 

 behind us impressions which we have imbibed from the idea of 

 mere freaks, hybrids, a return to primitive forms, and other mere 

 guesSes with which scientific literature abounds. On the table before 

 us, he observed, are the recent Proceedings of the Ro\-al Society 

 of Tasmania, in which is an account of a remarkable change in 

 a potato, a variety bi-ought from Scotland a few years previously, 

 known as Patterson's Victoria, a variety with white flowers and 

 round white tubers, which, after a culture of a few years in the 

 new climate, produced purple flowers, flat ovate tubers, and these 

 tubers with pink eyes. The members of that society looked at it 

 as a return to the original form of some hybrid variety. We 

 here, with other facts before us, would rather regard it as the 

 effect of environment operating on some innate, and so far un- 

 known, cause of change which might lie dormant through long 

 ages till the peculiar conditions of the environment called them 

 into active life. There seemed in fact seeds for form, as well 

 as seeds for individuals, awaiting the required conditions for 

 germination and rapid growth. In the one case we were able 

 to perceive and appreciate them, except in some of the lowest 



1 Principal Dawson bas suggested that one difficulty in the way of accept- 

 ing the prevalent theories of the evolution of man, comes from the fact 

 that anthropology arToids no "missing link" in the human skull. The 

 oldest hitherto found shows as full a development as in modern man. 



