274 



THE AMEBIC. I .V A' . I TFRA LIST 



[Vol. LV 



seems to be completely .lustificd by the results. As this expla- 

 nation is adequately outlined m tlie triinslated sunnnary further 



Th(> iuvestifrator's theory of factors located in each chromo- 

 nu're whicli fjovern the form of the chromosome, while con- 

 venietit in explaininjr the cause of the reunion of the chromo- 

 some fragments in maize, is scarcely necessary. Chromosomes 

 are not inherited as are the determiners for adult characteristics 

 in the form of minute chemical forerunners, but are passed on 

 complete in all respects. Consequently, factors to determine 

 their form in the next generation are not needed — the chromo- 

 some itself is carried over. Tlie actual form of the chromosome 

 has been shown by .Mc(Jlung, Wenrich, Carothers and others to 

 be determined largely by the location of the spindle fiber 



It is considered that the reviewed report has not clearly 

 demonstrated the origin of Zea Mays L. by means of chromo- 



1. The length of the selected chromosome complexes in the 

 forms particularly studied are not typical of the plant and 

 such selection gives a false impression of the acitual conditions. 



2. The figures illustrating the length dilTerenees of the homo- 

 logues composing the tetrads are not entirely convincing or 



If two types of srenetically fixed chromosome lensrths exist 

 i!i maize we would expect to find an expression of this difference 



tiiis dilTerence does not exist in ih.^ K, plants. 



Though there are reasons for not coiisMln-iii- that Kuwada 

 has proved his claims of the onuui o! Zm M(i>/^ L. he, never- 

 theless, is to be sincerely congratulated on an excellent cyto- 

 logical contribution involving great lalxn- and care. To the re- 

 viewer the apparent failure of Professor Kuwada to demonstrate 

 his main thesis dwindlas in impoitance wlien the value of the 

 "side issues" of the investigation are considered. Ilis work on 



