OF ENVIRONMENT 131 



EFFECT OF SOLUTIONS ON GERM-PLASM 



The idea that solutions of various kinds might 

 be introduced into the plant, and that modifica- 

 tions of the ontogenetic procedure might be thus 

 brought about, has been in the minds of many 

 workers in the laboratory. Developing inflor- 

 escences have been excised and set in vessels con- 

 taining salt solutions, and in other cases sub- 

 stances were applied to cut surfaces of the vege- 

 tative parts of the reproductive organs without 

 result. 



This in part was suggested to Darwin by vege- 

 table galls, and in the first chapter of the Origin 

 of Species (page 7) we find him saying: — 



" Such facts as the complex and extraordinary out- 

 growths which invariably follow from the insertion of 

 a minute drop of poison by a gall-producing insect, 

 show us what singular modification might result in the 

 case of plants from a chemical change in the nature of 

 the sap." 



That his interest in this matter was continued 

 is evidenced by the following from Life and 

 Letters: — 



" Shortly before his death, my father began to 

 experimentise on the possibility of producing galls arti- 

 iicially. A letter to Sir J. D. Hooker (November 3, 

 1880) shows the interest he felt in the question: — 



" ' I was delighted with Paget's Essay.^ I hear 



• Disease i» Plants, by Sir James Paget. Gardeners' Chronicle, 

 1880. 



