No. 529] 



ORGANIC RESPONSE 



87 



conceal rather than visualize the actual occurrences. 

 Direct germinal effects are undoubtedly secured in ovarial 

 treatments, and Tower's analytical cultures showed that 

 certain somatic characters induced directly might be 

 secured also by direct excitation of the egg. Such con- 

 currence of reaction may be expected especially with re- 

 gard to some qualities of simpler organization. Not so 

 readily interpreted are the responses of Sempervivum. 

 Alterations in size, number, and structure of floral organs 

 brought about by excitation during ontogeny are surely 

 not coordinate with changes in the germ plasm induced 

 simultaneously. In the case of Capsella the transference 

 to an alpine habitat of the plant in the shape of seeds is 

 followed by immediate and direct ontogenetic alterations 

 affecting a multitude of characters. Not until these so- 

 matic responses have been repeated, dozens, scores, or per- 

 haps hundreds of times, is an impression made on the 

 germ-plasm that allows it to carry the new characters in 

 the absence of the inducing. These facts suggest to us 

 that the soma is in the closest association with the germ- 

 plasm, has both theoretical and actual qualities different 

 from it, and any changes in these must inevitably be com- 

 municated, by the action of hormones or other physio- 

 logical mechanisms. 



A brief paraphrase of the foregoing discussion may be 

 useful in emphasizing some of the more important mat- 

 ters which have been touched upon. It is readily appar- 

 ent that the assumption of the inheritance of acquired 

 characters, after a long period of tolerance, with but 

 little research activity bearing upon its principal claims, 

 is coming in for a large share of attention from the ex- 

 perimentalist, and there seems a fair prospect that de- 

 cisive facts may be obtained within a period, very brief 

 in comparison with the century since the principal tenets 

 of the theory were first formulated. Already results are 

 available which have been obtained by cultures of animals 

 from paramoecia to mammals, and of plants from bacteria 

 to the higher seed-plants. 



A critical consideration of the available information 

 seems to justify the following generalizations: 



