378 ADAPTIVE VAEIATIONS. 



solution were then sowed in a solution to which 18.4 

 per cent, of salt had been added. After 5 days the 

 original normal Raulin culture showed no germination; 

 that originally kept one generation in salt Raulin solu- 

 tion showed slight germination, and that originally kept 

 two generations distinct germination. Thus the adap- 

 tation to a concentrated salt solution was not entirely 

 lost even after rearing in a normal medium, or was in 

 some degree inherited, especially in the case of the 

 greater degree of adaptation produced by the growth 

 of two generations in salt solution. Doubtless this 

 " inheritance of acquired characters " was due to the 

 salt solution influencing the germ cells at the same 

 time as the body cells. The same explanation may be 

 used to account for the somewhat similar results ob- 

 tained by Ray * with Sterigmatocystis alba. Oonidia 

 of this mould were sown in a solution of dextrose, the 

 development taking place but slowly, owing to the want 

 of adaptation to the new environment. On continuing 

 the culture in the sugar solution, however, the rate of 

 development gradually increased from generation to 

 generation, till, finally, the sixth generation showed a 

 more abundant development after 8 days than the first 

 one had after 15 days. The morphological characters 

 were progressively modified in addition, so that the 

 mould came finally to resemble a penicillium. 



In the members of the Animal Kingdom, the power 

 of adaptation is, as a rule, far less marked than in those 

 of the Vegetable Kingdom, but probably it is present 

 to a greater or less extent in all organisms, from the 

 lowest to the highest. In certain Flagellata, for in- 

 *Rev. Gen. de Bot., ix. p. 193, 1897. 



