MUTATION IN PLANTS.' 



I). T. MACDOUC'.AI.. 



Ir is presumably safe to say that all stiulciits ol natural his- 

 tory a^ec in the opinion that livinj; matter has qualities at the 

 present time that it did not ori;(inally, or always i>ossess, and 

 furthermore it is universally conceded that protoplasm is under- 

 going such development that it is constantly accjuiring new proj>- 

 erties, and taking form in an increasing number of tyjK's, kinds, 

 or species of organisms as a consequence. In other words living 

 matter is increasing the number of its qualities, multiplying the 

 number of forms in which these qualities are variously gr(»uj)ctl, 

 and at the same time undergoing such differentiation that an 

 increasing complexity is the general tendency of the organic 

 world. These facts once realized the biologist finds himself 

 confronted with two stupendous interrogatories. Hy what 

 method is the general development and differentiation of 

 organisms brought about as exjjressed in the formation or 

 origin of new species, and secondly what are the general fac- 

 tors which shape this progression ? The amount of mere dis- 

 cussion ensuing fn^m the presentation of conflicting views 

 brought out by these questions, in comparison with the total 

 scientific effort to obtain positive evidence upon the ix)ints 

 involved is appalling to contemi)late. Happily the biological 

 world is becoming intolerant of wrangling and siK-cuIative con- 

 tentions, and has earnestly set about finding the facts that will 

 afford an adequate and satisfactory solution to the main i)robIems. 

 The cult of the study of statistical variations may be regardetl as 

 one expression of this newly assumed attitude, while the devious, 

 intricate and oft-times labyrinthine ways of cytological invest i- 



iThe general disciis.sion of the mutation theory embodied in this paper, 

 together with an exhibition of the seedlings of CKnothera wxs given before the 

 Zoological Seminar of Columbia University, April 23, 1903. The comparisons 

 between the mutants were not completed until August, 1903. 



737 



