



A TA VI SM OR RE VERSION. 



it does not pass from skin to mucous membrane, never- 

 theless, as in the case of the flower, it now and then 

 indicates its ancestry by reverting to its original type of 

 structure. 



Spurious Atavism. It is so important not to con- 



FiG. 79. A congenital fold of skin stretching from the thigh 

 to the heel of a girl. (After Wolff.) 



found spurious instances with examples of genuine 

 reversion or atavism that, even at the risk of being 

 tedious, it is necessary to consider briefly a few in- 

 teresting cases likely to be misinterpreted on superficial 

 examination. 



In 1888 Dr. Julius Wolff, of Berlin, published a 



