Modification of Germinal Constitution of Organisms 199 



through a process of hybridization. On the high volcanic 

 plateau of Toluca there is another type rather closely allied 

 to L. midtitaciiiata, which is also suggestive of having arisen, 

 or of being in the process of arising, through hybridization. 



These conditions in nature are of course difficult or 

 impossible to check and verify, because the past is absolutely 

 unkno\"vTi, and little or no indication of what it has been 

 can be obtained from any source. The materials in muse- 

 ums and the records by systematists are utterly useless for 

 this purpose. Apparently the only way of attacking this 

 problem is the one which I have adopted of placing colonies 

 in isolated locations, or in cages, there to carry out the 

 process of interbreeding and forming of hybrid combina- 

 tions as they would occur in nature. 



In the last few years at Tucson a series of experiments 

 has given an exact duplication of the "mutation behavior," 

 and further, it is clearly called into operation by conditions 

 external to the organism. At first a race was synthetized 

 and was and is still constant, but when placed under opti- 

 mum conditions of growth and development at Tucson it 

 has given fourteen distinct t}-pes. Some of these had in 

 previous experiments been tested out and are known to breed 

 true, and others are still to be tested. 



With plants, Gates and Davis are endeaxoring to pro- 

 duce synthetically O. Lamarckiana from a hybridization of 

 0. graiidijlora and 0. bioinis, and while as yet 0. Lamarcki- 

 ana has not been produced, Davis has obtained a tjq^e which 

 he considers to be very close thereto. It is perhaps not 

 too much to expect that in the near future O. Lamarckiana 

 will be experimentally s}mthetized. 



If it proves to be generally true that "mutation behav- 

 ior" is a sequence of synthetic composition, it does not in 



