April 15, 1898.] 



SCIENCE. 



m^ 



if any food adulterant runs more than a 

 short course now, the fault must be charged 

 to ineiiicient food laws. 



Let us protect the honest manufacturer 

 and dealer at every point against the unfair 

 competition of dishonest rivals. Let our 

 products stand on their own merits — stand 

 or fall. And let the same rule apply to im- 

 ported goods. 



I have tried to obtain refined cotton- 

 seed oil from our leading grocers, but have 

 rarely succeeded except at four times its 

 value and under another name. Our na- 

 tive wines, superior to the common wines 

 of any other country, are creating for them- 

 selves an increasing demand in foreign 

 countries under their proper labels. Why, 

 then, should we allow them to receive ficti- 

 tious names at home ? Let us by all proper 

 means promote the use of American maize 

 at home and abroad, but always as maize 

 — not as wheat ! Let us eat plain American 

 herrings, if we choose, but not ' French sar- 

 dines ' from the coast of Maine. Let us stop 

 the sale of ' pure imported Lucca oil ' from 

 the cotton fields of Georgia. Whether as a 

 matter of morals or from policy, let us have 

 honestjr. 



W. D. BiGELOW. 



COLOR VISION. 

 Of late years the subject of color vision 

 seems to have been specially stimulating to 

 students of psychology, if a judgment may 

 be based upon the rapid increase in the 

 number of hypotheses advanced to explain 

 it. The last of these is briefly outlined in 

 a recent issue of Science (Feb. 18, 1898), 

 having been brought forward by Professor 

 Patten, of Dartmouth College, at the meet- 

 ing of the American Physiological Society 

 during Christmas week, and based upon his 

 observation of the fibrils in the eyes of in- 

 vertebrates. On the assumption "that the 

 length and angular relations of a fibril de- 

 termine the amount of its response to a 



wave of light of a given length and plane 

 of vibration, it is possible to offer a logical 

 explanation of many phenomena of color 

 vision." 



Every investigator recognizes the neces- 

 sity of hypotheses as antecedent to theories. 

 The contrast between these may be briefly 

 expressed in the definition of Flourens : " A 

 hypothesis is the explanation of facts by 

 possible causes ; a theory is the explana- 

 tion of facts by real causes." The wave 

 theory of light was a hypothesis until it be- 

 came fortified by a mass of evidence, math- 

 ematical and experimental. The most 

 important single experiment was that of 

 Foucault, who showed that on passing from 

 air into water the velocity of propagation 

 of light is diminished, as it should be ac- 

 cording to the wave theory, while according 

 to the emission hypothesis it should be in- 

 creased. This crucial experiment alone 

 would have been sufficient to change the 

 wave hypothesis into a wave theory. Pro- 

 fessor Patten's view of color vision is an- 

 nounced as a ' new theory.' This word is, 

 indeed, so generally employed as a synonym 

 for hypothesis that it may, perhaps, be as 

 well to accept the mandate of usage, insist- 

 ing always, however, upon a distinction be- 

 tween established and unproved theories. 

 No existing theory of color vision has been 

 established upon evidence comparable with 

 that on which the wave theory of light 

 rests. This fact should not prevent psy- 

 chologists from forming and testing new 

 hypotheses ; but when there is so large a 

 number of these offered for choice in rela- 

 tion to a single subject all persons other 

 than the originators have good excuse for 

 conservatism. Any one whose domain is 

 not psychology should be content with in- 

 definite suspense of judgment until psychol- 

 ogists quite generally agree upon one theory 

 of color sensation, as physicists have agreed 

 upon one theory of propagation of the 

 waves which give rise to color. 



