8 PROBLEMS OF GENETICS 



more obscure if read in connection with the essay on "Generatio 

 Ambigena," where he expresses the conviction that the Medulla 

 is contributed by the mother, and the Cortex by the father, both 

 in plants and animals. 5 



But however that may be, he regards this original diversity 

 as resulting in the constitution of the Natural Orders, each rep- 

 resented by one individual. 



In the second aphorism the Omnipotent is represented as 

 creating the genera by intermixing the individual plantae classicae, 

 or prototypes of the Natural Orders. 



The third statement is the most remarkable, for in it he 

 declares that Species were formed by the act of Nature, who by 

 inter-mixing the genera produced Species congeneres, namely 

 species inside each genus, to the number which now exist. 

 Lastly, Chance or Accident, intermixing the species, produced 

 as many varieties as there are about us. 



Linnaeus thus evidently regarded the intermixing of an 

 originally limited number of types as the sufficient cause of 

 all subsequent diversity, and it is clear that he draws an an- 

 tithesis between Creator, Natura, and Casus, assigning to each 

 a special part in the operations. The acts resulting in the 

 formation of genera are obviously regarded as completed within 

 the days of the Creation, but the words do not definitely show 

 that the parts played by Nature and Chance were so limited. 



Recently also E. L. Greene 6 has called attention to some 

 curious utterances buried in the Species Plantarum, in which 

 Linnaeus refers to intermediate and transitional species, using 

 language that even suggests evolutionary proclivities of a 

 modern kind, and it is not easy to interpret them otherwise. 



Whatever Linnaeus himself believed to be the truth, the 

 effect of his writings was to induce a conviction that the species 



5 Amoen. Acad., 1789, vol. 6. I do not know whether attention has been called 

 to the curious mistake which Linnaeus makes in the course of this argument. He 

 cites the differences between the Mule and the Hinny in illustration of his thesis, 

 pointing out that the Mule is externally more like a horse and the Hinny more like 

 an ass. This, he says, is because the Mule has the horse for a father, and the 

 Hinny the ass, thus inverting the actual facts! 



6 Proc. Washington Ac. Set., 1909, XI, pp. 17-26. 



