September 13, 1901.] 



SCIENCE. 



405 



increased pressure at the organ pipe brings 

 out the strong octave c'". 



Stability of vibration. Vibrational hysteresis. — 

 Finally, the peculiar phenomenon observed 

 in connection with the stability of vibra- 

 tion deserves special mention. A Konig 

 resonator mounted on a graduated slide, x, 

 is convenient for the purpose. If the mouth 

 of this apparatus is approached slowly from 

 a large distance, x, to within 2.2 cm. of the 

 lip, c" is strongly resounded. On passing 

 these limits, d" breaks forth almost sud- 

 denly. With this d" sounding from the 

 combined system, withdraw the resonator 

 slowly again ; d" will be retained until x 

 has increased to 2.8 cm., about. Hence, 

 within 6 mm. of approach, the note is 

 either c" or d", depending upon whether 

 the position has been reached from large 

 or from small values of x, within the limits 

 given. See figure. With a carefully reg- 

 ulated slow influx, 9 or even 10 mm. of 

 range were attained with a sharp clicklike 

 breakdown at each end. The change from 

 c" to d" is usually more sudden, that from 

 d" to c" more gradual, perhaps, but the 

 hysteresis-like character of the phenomenon 

 is unmistakable. As I have recently been 

 studying hysteresis * from diflerent points 

 of view (cf. forthcoming paper in the Phys- 

 ical Review J on temporary set) , the present 

 purely vibrational case of it is to me strik- 

 ingly interesting. 



Carl Bartjs. 



Brown University. 



THE FIFTH INTERNATIONAL ZOOLOGICAL 



CONGRESS. 



The Fifth International Zoological Con- 

 gress held its sessions in Berlin from August 

 12 to August 16, under the gracious pro- 

 tection of His Highness the Crown Prince 

 of Germany and the presidency of Pro- 

 fessor K. Mobius, and, so far as concerns 

 the attendance, was the most successful of 



'^American Journal of Science, XI., 1901, p. 97. 



all that have so far been held. Most of the 

 countries of Europe were well represented, 

 delegates were present from Canada, Brazil, 

 Mexico and the United States, the total 

 number of those present being considerably 

 over six hundred. The members in at- 

 tendance from the United States were : Pro- 

 fessors E. B. Wilson, of Columbia Uni- 

 versity, and Patten, of Dartmouth College; 

 Dr. Stejneger, of the Smithsonian Institu- 

 tion ; Dr. C. W. Stiles, of the National 

 Museum ; Mr. W. A. Murrell, of Cornell 

 University ; Mr. J. Hunter, of St. Louis, 

 and Professor J. Playfair McMurrich, of 

 the University of Michigan. Owing to the 

 large number of papers to be presented, 

 seven sections were established, namely, 

 general zoology, experimental zoology, ver- 

 tebrata (biology and systematic), verte- 

 brates (anatomy and embryology), everte- 

 brata (exclusive of arthropoda), arthropoda 

 and nomenclature ; and while such a sepa- 

 ration of subjects was undoubtedly neces- 

 sary and the grouping as satisfactory as 

 might be, it made it impossible to attend 

 the reading of many of the papers in which 

 one might be interested. 



The papers read were very varied in 

 character, some being on special subjects, 

 some, indeed, altogether too special for such 

 a meeting, and others on the more general 

 problems of zoology. If a single subject is 

 to be selected as that which awakened the 

 greatest interest, the new or rather the re- 

 kindled struggle between vitalism and 

 mechanism must be the one chosen. 

 Driesch, who has precipitated the renewal 

 of the struggle, presented his views to a 

 well-attended meeting of the section of ex- 

 perimental zoology, upholding, in a forcible 

 and clearly stated argument, the vitalistic 

 side of the question, while, in the discussion 

 which followed, Ziegler, Roux and Rhumbler 

 took the opposite side, maintaining that it 

 is too early yet to admit the existence of 

 vitalism or to postulate an active purpose- 



