CHAPTER XL 

 BIRTH-MARKS AND TELEGONY 



TWO widely-spread " beliefs " in regard to the 

 complicated and not generally familiar subject of 

 the reproduction of animals are, in addition to that 

 dealt with in the last chapter, examples of the unjustified 

 and primitive mode of forming a conclusion known as 

 "post hoc ergo propter hoc." I refer, firstly, to the 

 belief (which I have already mentioned) in the causation 

 of what are called " birth-marks " by " maternal impres- 

 sions," by which is meant the seeing of unusual and 

 impressive things by the mother when with child ; and, 

 secondly, to the belief that a thoroughbred mare can 

 be so affected or infected by the sire (say a zebra) of 

 one foal as to convey to the foal of a later sire (say, a 

 thoroughbred like herself) marks (such as stripes on 

 the legs) which were not present in the second sire, 

 though present in the first sire. This supposed occur- 

 rence is called "telegony," and is by some persons 

 supposed to occur in dogs, cattle, and other animals, 

 including man, as well as in the horse. 



There is little support in ordinary experience for the 

 belief that birth-marks are caused by maternal impres- 

 sions, although some of those who are concerned in a 

 professional way with breeding operations cling to it. 



In very ancient times we find that there was a belief in 



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