THE PLANT 41 



The ground we have covered would require several large 



volumes for any adequate presentation, even of the 



established facts, unless such presentation 



were made in severely technical language; 

 Scaffolding. 



but enough has probably been said to show 



that there is no longer any need to indulge in vague gener- 

 alities about vitality, suitable climate, and so on, and that 

 it is possible to assign numerical values to the quality 

 of the cultivator's work. It now remains to examine 

 the scaffolding itself, and its load of fruits, built by the 

 plant under the control of its inherited tendencies as 

 reacted upon by environmental agencies, and itself con- 

 tinually acted upon in the same way. 



And here it may be excusable to insert a small comment 

 on the difficulty which many persons feel in accepting 

 recent interpretations of this reaction. Their 

 a ;* e objection may be summarized in such a case 

 as the following : They have grasped the idea 

 of the chemical defmiteness of a pure strain, character- 

 ized, let us say, by a 30-millimetre lint ; but when they 

 find that a 35-millimetre lint is obtained from this strain 

 on cultivation under some particular set of conditions 

 (cf. Figs. 14 and 15), they object that it must be nonsense 

 to speak of any definiteness in the inheritance or manifes- 

 tation of such variable characteristics. A simple parallel 

 will best illustrate the falsity of the objection. Certain 

 strains of the Chinese primrose are known which breed 

 true to white, whatever the conditions under which they 

 are grown ; there are also other white strains which remain 

 white when grown in a cool greenhouse, but turn pink 



