INERTIA AS RELATED TO HEREDITY 85 



human equivalent of hibernation in lower mam- 

 mals or lower vertebrates.* The night-terrors of 

 children and their as wonderful day-dreams and 

 fictions are by no means always to be traced to an 

 environmental origin. Dr. Guthrie, writing on this 

 topic in Allbutt's "System of Medicine/' relates a 

 case " of a lady who in her desire that her children 

 should learn nothing but what is true, banished fairy 

 tales from her nursery. But her children evolved, 

 from their own imaginations, fictions that were so 

 appalling that she was glad to divert them with 

 'Jack the Giant-killer/ " f The physical basis of 

 inheritance has for some time now been admitted 

 by embryologists to be the nucleus. As Professor 

 Wilson J writes, "The nucleus cannot operate 

 without a cytoplasmic field in which its peculiar 

 powers may come into play. But this field is 

 created and moulded by itself. Both are necessary 

 to development. The nucleus alone suffices for the 

 inheritance of specific possibilities of development." 

 Summing up on the subject of inheritance this 

 author thus expresses himself, " Normal develop- 

 ment is in a greater or less degree the response of 

 the developing organism to normal conditions. But 

 neither can we regard specific forms of development 

 as directly caused by the external conditions, for 



* M. de Manaceine, " Sleep," Contemp. Science Series, p. 326. 

 (London: W. Scott, 1897.) 



t Leonard Guthrie in Allbutt's " System of Medicine," vol. viii. 

 p. 227. 



$ E. B. Wilson, " The Cell in Development and Inheritance," 

 p. 327. (Macmillan, 1898.) Ibid. p. 326. 



