108 BIOLOGY AND SOCIAL PROBLEMS 



mander Proteus. This inhabitant of caves 

 when reared in its natural dark surroundings 

 is without much pigment and consequently of 

 a delicate flesh-tint. When reared in the light, 

 it develops a well-marked dark coloration. The 

 newly born descendants of such dark parents 

 emerge at once as dark individuals as though 

 this peculiarity had been transmitted to them 

 from their parents. But as Kammerer, who 

 has recently studied this problem, has pointed 

 out, the body of Proteus is so translucent that 

 the light can reach and affect its germ cells 

 and thereby influence the next generation, as 

 well as modify its somatic cells. In conse- 

 quence of this semi-transparency light can 

 affect the interior of Proteus as a temperature 

 change can that of most lower animals. Possi- 

 bly in some such way as this are to be explained 

 Kammerer's later results on the spotted sala- 

 mander of Europe. This animal becomes 

 lighter in color when reared on a light clay 

 background and darker when reared on a dark- 

 earth background, and the descendants of two 

 such stocks show at once the parental acqui- 

 sitions. Kammerer regards this as a conclusive 

 case of the inheritance of acquired characters, 

 but before it can be so accepted, it must be 



