SPIRITUAL THEORY OF CONCEPTION 229 



and butterflies) may have been noticed by primitive man, 

 and have started the belief that there are fertilising spirits 

 or demons in the air. However the fancy arose, it is 

 only a parallel to the strange fancies as to spontaneous 

 generation of all sorts of animals and plants current 200 

 years ago among civilised men. And, further, it is worth 

 noting that the uncanny belief in the " incubus " which was 

 generally prevalent in the Middle Ages may possibly be 

 considered as a survival in (or incursion into) Europe of 

 the primitive spiritual theory of all human conception, and 

 of the fertilising activity of the haunting spirits of the air 

 which was held by primeval man, and is still found in full 

 force among the Arunta tribes of Australia. 



