212 TRANSMISSION OF ACQUIRED* CHARACTERS 



of functionally established variations that are hereditarily trans- 

 mitted. But this is a non-sequitur, since the modifications may 

 reappear merely because they are re-impressed directly on each 

 successive generation. It is Misunderstanding IV. 



At the same time it should be noted that radical change of en 

 vironment may induce germinal variations or mutations which 

 breed true. These must be distinguished from modifications, as 

 already explained, since we cannot interpret them physiologically 

 as the direct somatic results of the environmental change. 



Another case requiring consideration is that of a Turkestan 

 relative of our common Shepherd's Purse (Capsella bursa pastoris). 

 It has apparently spread from the low country to the uplands, and 

 the specimens growing at the higher altitudes are smaller than those 

 below, and pink instead of white. Seeds of lowland forms sown in 

 the uplands develop into small plants with pink flowers, but the 

 upland forms keep their characters (except the xerophytic leaves) 

 when grown in the low country. It is possible that we have here 

 to do with a variation coincident with a modification ; it seems, 

 however, that the experiments require to be repeated and extended. 



Experiments on Brine-shrimps. Reference is often made 

 to the observations and experiments of Schmankewitsch (1875) 

 on certain brine-shrimps belonging to the genus Artemia. By 

 lessening the salinity of the water he was able to transform one 

 type, Artemia salina, in the course of generations into another 

 type, Artemia milhausenii. By increasing the salinity, he was 

 able to reverse the process. Although he did not himself make 

 any such claim, his work has often been referred to as an illus- 

 tration of changing one species into another, and of the inheritance 

 of acquired characters. 



It seems very doubtful, however, whether we have here to 

 do with modifications at all. Schmankewitsch did not modify 

 any one Artemia salina into Artemia milhausenii ; with a pro- 

 gressively changing environment and in the course of generations 

 he observed a transition of the population from the one type to 

 the other ; it is probable that the change of salinity operated 



