202 THE GERM-PLASM 



on this subject * cannot be considered to be an impartial one, 

 if no mention is at the same time made of the fact that all these 

 suggestions remained unnoticed, and had no effect on the prog- 

 ress of scientific thought. That this is the case there can be 

 no doubt. And although it may be a satisfaction to every one 

 to have expressed a correct idea, no such idea can be con- 

 sidered as fertile, and as having an important influence on the 

 progress of scientific thought, unless its meaning is so obvious 

 that it results in further progress. Such a result, however, only 

 followed after my essays had appeared. 



4. Objections to the Theory of the Germ-plasm 



Important objections to this theory have been raised by 

 several botanists ; and at first sight the facts on which these 

 are based may easily give rise to the impression that the 

 theory cannot be carried out in the case of plants. If this were 

 so, however, its correctness would be altogether doubtful, for the 

 hereditary mechanism cannot be totally different in plants and 

 animals. We must therefore make a closer examination into the 

 facts as they concern plants, and I hope to be able to show that 

 the fundamental ideas which I have assumed are applicable to 

 plants as well as to animals, although they did not originate 

 from the botanical point of view. 



Certain misconceptions and inaccurate representations must 

 first be put on one side. Many botanists deny the existence of 

 the germ-plasm entirely. 



Vines t considers the assumption of a special 'reproductive 

 substance' unnecessary, as the capacity for reproduction is a 

 fundamental property of protoplasm. A cutting gives rise to a 

 complete plant, just as a broken crystal becomes complete when 

 immersed in the mother-liquor, for it produces the missing 

 parts, viz., roots. It is not necessary to assume the existence ot 

 a special 'reproductive substance' in either case. 



I need not especially emphasise the fact that this stimulus 

 which results in the completion of a part is not by any means a 

 universal phenomenon, and that, for instance, some parts of 

 plants cannot be reproduced from cuttings. I shall simply 



* Cf. the account given in Geddes and Thomson's ' Evolution of Sex,' 

 pp. 93 and 94. 



t C/. ' Nature,' Oct. 24, 1889 ; and ' Lectures on the Physiology of 

 Plants,' Cambridge, 1886. 



