ACQUIRED CHARACTERS 83 



been advanced to show the inheritance of acquired 

 characters are simply transient hold-over somatic 

 effects that have gained no permanent grip upon the 

 hereditary stream of germplasm, and which conse- 

 quently soon fade away. 



In a similar way the gradual acclimatization of the 

 mold, Penicillium, to a salt solution of a density suffi- 

 cient to cause its death if placed in it at once, has been 

 effected, and the resulting spores have produced molds 

 that are able to survive in the concentrated solution. 

 Here, of course, the spores have been acclimatized as 

 well as the parent plant and it was to be expected that 

 these spores would develop into molds habituated to 

 the increased saline environment. This, however, is 

 pseudo-heredity, for no permanent method of response 

 has been established. 



/. Prenatal Influences 



Perhaps the most illogical and at the same time the 

 most widespread of all types of supposed transmis- 

 sion of acquired characters are the so-called "maternal 

 impressions." The prevalence of this superstition has 

 caused expectant mothers untold needless misery. 



Popenoe and Johnson, after an excellent and ex- 

 tended discussion of the matter, conclude as follows : 



"To recapitulate, the facts are 



(1) That there is, before birth, no connection be- 

 tween the mother and child, by which impressions on 

 the mother's mind or body could be transmitted to the 

 child's mind or body. 



