Apeil 3, 1914] 



SCIENCE 



487 



sider the types of differences — variations — 

 which exist in so far as they may effect the 

 result with which we are chiefly concerned. 



Beginning at an early period in the his- 

 tory of evolution with the idea that all 

 variations might be inherited, results soon 

 suggested that the characters due solely to 

 surrounding influences such as food supply, 

 etc., were not thus transmitted. These were 

 called fluctuating variations. On the other 

 hand, variations due to the structural 

 changes in the germ cells which were passed 

 on from one generation to another have 

 been spoken of as inherited variations. 



The evidence at present indicates that 

 farther subdivisions must be made and that 

 normal inherited variations consist of two 

 quite distinct classes. The variations where 

 the results are due to the interaction of 

 factors in accordance with Mendelian prin- 

 ciple, and which, adapting a term used by 

 Plate (1913), may be called amphimutations 

 inasmuch as the condition is due to the 

 mingling of two lines of descent, the other 

 variations, as a class, in which the results 

 — evolution in the abstract — are due to a 

 series of units added as increments, may 

 well be called cumulations. It is quite evi- 

 dent that the term ' ' mutation ' ' can not con- 

 tinue to include both types. As a coordi- 

 nate term fluctuating variations may be 

 spoken of as fluctuations. 



Under abnormal variations must be 

 classified forms ranging from monstrosities 

 to slight departures from the ordinary con- 

 dition, some of which are undoubtedly due 

 to the losses or modifications of unit char- 

 acters through the action of extraordinary 

 stimuli, while others may be due to abnor- 

 mal and unequal distribution of chromo- 

 somes occurring at the time of their divi- 

 sion. The idiomutations of Plate are here 

 included. 



The answer to the question as to the 

 progress made in the application of evolu- 

 tion to the creation of new forms rests in 



the statement that the attack on the prob- 

 lem is becoming more concentrated. The 

 selection of fluctuations has been tried and 

 has failed. Efforts by means of amphimu- 

 tations end in a maze of circles with no evi- 

 dent progress. Idiomutations, so far as 

 one may judge from the evidence, present 

 retrogression rather than advancement. It 

 is by means of pure lines under normal 

 conditions that one may search with advan- 

 tage for cumulations, the units by which to 

 build the new. There the evidence wiU be 

 unobscured either by the pyrotechnics of 

 Mendelian formulie, or by the factitiousness 

 of abnormal stimuli. Fluctuations wiU be 

 present, but statistical methods will permit 

 their evaluation. Should the measurement 

 of the mean in the tenth or even the one 

 hundredth generation present no advance- 

 ment, failure is not necessarily implied. 

 Nature has devoted fifty millions of years 

 or more to her work. There should be no 

 discouragement if a few paltry years of in- 

 vestigation fail in duplicating her methods. 

 It is with a feeling not unmixed with 

 pessimism, however, that one views the con- 

 ditions under which work of the character 

 outlined must evidently go forward. Those 

 engaged in teaching have with a few excep- 

 tions time for little more than an occasional 

 investigation of limited scope, particularly 

 in a field which requires continuous appli- 

 cation. Governmental departments where 

 it could best be taken to a successful issue 

 have only too often been subservient to 

 political policies which demand immediate 

 results. An ounce of compiled compendium 

 is — to them — worth more than a ton of 

 painstaking investigations which makes an 

 advance on a theory. Looking a few gen- 

 erations into the future is not their con- 

 cern." A remedy for such conditions clearly 



6 Exceptional work has been done by those more 

 or less closely connected with certain State Agricul- 

 tural Experiment Stations. The names of East and 



