520 



SCIENGE. 



[N. S. Vol. VII. No. 172. 



tented ignorance we can maintain until our 

 friends, the psychologists, finally settle 

 upon some one theory after this is fortified 

 with evidence of such a character as to ex- 

 clude its competitors. Their authority will 

 then be accepted as readily as they now ac- 

 cept the authority of the physicists about 

 the polarization of light or the mechanical 

 equivalent of heat. 



So far, therefore, as physicists accept the 

 Young and Helmholtz hypothesis their ac- 

 ceptance must be based, not on any physio- 

 logical grounds, but upon its convenience 

 of application to the phenomena of color 

 mixture and color analysis. Practically, 

 one hypothesis may, perhaps, be no better 

 than any other for this purpose, If we 

 abandon the term ' primary color,' and sub- 

 stitute ' prominent color ' for it, our selec- 

 tion may be determined avowedly by con- 

 venience. In the performance of the ex- 

 tended work of color analysis, which was 

 undertaken a few yeai-s ago under the di- 

 rection of Professor Rood for a well-known 

 firm of publishers, tlie composition of all 

 compounds was expressed in terms of black, 

 white and five 'standard colors,' red, orange, 

 yellow, green and blue. The standard pig- 

 ments selected were English vermilion, min- 

 eral orange, chrome yellow, emerald green 

 and ai'tificial ultramarine, all of which give 

 enduring and reliable hues. Violet was left 

 out because no sufficiently reliable pig- 

 ment was obtainable; but by mixture of 

 appropriate proportions of standard red, 

 blue and black a good violet was included 

 in a selected series of types. There is no 

 danger of practical inconvenience to the 

 physicist because of the present unsatisfac- 

 tory conditions relating to color theory. 



To give the outlines of the competing 

 views is hardly necessary. The Hering 

 hypothesis is well known, and probably 

 universally rejected among physicists. 

 Wundt's hypothesis has a good following 

 among psychologists, but is still very little 



known among physicists. Without pre- 

 tending to be a psychologist, I am much 

 more favorably impressed with this hy- 

 pothesis than with that of Hering. Mrs. 

 Franklin's views need not be outlined, as 

 they are readily accessible, in either the 

 English or German language. With the 

 hypotheses of Ebbinghaus and Nicati I 

 have not yet become acquainted. Physicists 

 will, perhaps, not be surprised at this frank 

 confession. 



W. Le Conte Stevens, 

 Eensselaee Polytechnic Institute, 

 Teoy, N. y. 



THE EP ARTERIAL BRONCHIAL SYSTEM OF 

 THE MAMMALIA. 



The paper deals with the structure of the 

 bronchial system and pulmonary vascular 

 supply of the mammalia as exhibited by 

 corrosion in an extensive series comprising 

 representative types of all orders and many 

 families. The conclusions reached are, in 

 the main points, at variance with the views 

 expressed by Professor Aeby and generally 

 accepted in the current text-books of Hu- 

 man and Comparative Anatomy. For rea- 

 sons given in detail in the paper, the prim- 

 itive form of the mammalian bronchial 

 distribution appears to be Aeby's ' bilateral 

 hyparterial type.' The arrangement of the 

 primary bronchial trunks and of the pul- 

 monary artery exhibited in this type is of 

 considerable morphological importance in 

 reference to the evolution of the typical 

 mammalian bronchial ti"ee, and is discussed 

 at length in the paper. Aeby's researches 

 revealed but a single form possessing this 

 distribution, viz.: Hystrix cristata, the Euro- 

 pean Porcupine. Subsequently, M. Weber 

 described the same type in the lungs of 

 Balcena mysticetus and B. antipodum. The 

 present investigations have added a fourth 

 form to the list, Taxidea americana, the 

 American Badger. 



In examining the lungs of the remaining 



