6o4 THE WONDER OF LIFE 



grams. When the germ cells come to develop into 

 oSspring, these engrams may have an influence — a specific 

 influence. Appropriate hberating stimuh of the nature 

 of the original change in the energetic situation will call 

 forth the latent engrams. This is called ' ekphory '. 



In support of his mnemic theory of heredity Semon 

 cites, among other facts, Kammerer's experiments on the 

 Nurse-Toad {Alytes obstetricans). Unlike ordinary toads, 

 the female lays her eggs on land, and the male who assists 

 in the process gets them glued on his hind legs. Moreover, 

 the eggs are larger than usual, with more yolk, and fewer 

 in number. 



Kammerer kept the toads at a relatively high temperature 

 (25°-30° C.) and thus induced them to seek the water, 

 where the egg-laying and fertilization took place. The 

 gelatinous envelopes of the eggs which had remained sticky 

 and imswoUen on land, now swelled up as usual, and as they 

 woidd not adhere to the male's legs, the eggs developed 

 in the water. After several breeding periods the toads 

 became accustomed to the water ; they also laid more 

 numerous and smaller eggs. 



But the more important fact is this, that the ofispring 

 of the toads showed a change of habits hke that of their 

 parents. When they became sexually mature they sought 

 the water, even when kept at the normal temperature, 

 and laid their eggs there. The fourth generation showed 

 a re- appearance of the doubtless ancestral swollen pad on 

 the forefinger of the male, which was absent in the race of 

 nurse-toads with which Kammerer experimented. In 

 Semon's phrase the appropriate stimuh called forth the 

 latent ancestral engrams. 

 . Provisional Conclusion. — ^It may be that there is 



