18 THE AMERICAN NATURALIST [Vol. XLV 



young and the reproductive habits resembled those of 

 S. atra. The conditions of these experiments are not 

 such as to allow a definite separation of somatic and ger- 

 minal effects, neither was the permanency of the newly 

 acquired habits tested to such an extent as to determine 

 their hereditary value. That characters and habits may 

 be modified in such manner as to appear in the next gen- 

 eration or two in the absence of exciting conditions is il- 

 lustrated by hundreds of authentic examples in plants 

 which have long been known. 1 2 



My own earlier work with relation to this subject con- 

 sisted chiefly of ovarial treatments in which the main 

 and accessory reproductive elements of seed-plants were 

 subjected to the direct action of solutions of various 

 kinds. New combinations of characters constituting a 

 distinct elementary species or genotype were obtained in 

 one plant, and the divergent type has been found to trans- 

 mit its qualities in the fullest degree as far as tested, to 

 the fifth generation. Still more marked forms were ob- 

 tained in a second genus, the divergent progeny being 

 lost in transference to the Desert Laboratory, while 

 marked responses have been obtained in the extensions 

 of these experiments upon species representing widely 

 different morphological types in Arizona. The greater 

 majority of the tests have been made upon plants grow- 

 ing under natural conditions, so that environmental" reac- 

 tion in addition to that of the specific reagents might be 

 excluded. Progenies representing many species, in- 

 cluding thousands of individuals, many of which are di- 

 vergent, are now under observation. Absolute finality 

 of decision with respect to the standing of the new types 

 may be reached but slowly. 



Gager produced chromosomic aberrations in the reduc- 

 ing divisions of (Enothera by irradiations and such excita- 

 tion was also followed by the appearance of aberrants in 

 the progeny, the hereditary qualities of which have not 



