A CCLIMA T1ZA TION. 779 



long, which had been exhausted to such a high degree that no 

 electrical discharge would pass through it. It seemed, therefore, 

 to have an infinite electrical resistance. No cathode beam could 

 be generated in it; nevertheless, by moving suitable disks of 

 fluorescent matter from point to point in the tube by means of an 

 outer magnet which attracted bits of iron on the disks, Lenard 

 showed that the cathode beam passed through the vacuum. En- 

 ergy passed into the vacuum and could be detected from point to 

 point. We can conceive of its passing through the ether in the 

 tube by a wave motion, but not by a molecular movement, for 

 there were no molecules to move. The molecular bombardment 

 must have stopped at the aluminum window, and the resulting 

 energy may have been propagated by ripples in the ether. This 

 experiment of Lenard seems to me the most interesting one in the 

 subject of cathode rays. The greatest mystery, however, which 

 envelops the subject is the action of the X rays on bodies charged 

 with electricity. When the rays fall on, for instance, a charged 

 pith ball, the charge disappears. A positive as well as a negative 

 charge is dispelled by the X rays. The energy of the medium 

 about the pith ball is changed to a marked degree, and in this 

 phenomenon we seem to be brought closer to a wave theory in a 

 medium than to a molecular theory of movement of matter. 



ACCLIMATIZATION. 



By WILLIAM Z. RIPLEY, PH. D., 



ASSISTANT PROFESSOR OF SOCIOLOGY AND ECONOMICS IN THE MASSACHUSETTS INSTITUTE OF 

 TECHNOLOGY ; LECTURER IN ANTHROPO-GEOGRAPHY IN COLUMBIA UNIVERSITY, NEW YORK. 



SECOND PAPER. 



WHAT is the first effect of a tropical climate upon the 

 human body and its functions ? * The respiration becomes 

 more rapid for a time, although it soon tends toward the nor- 

 mal ; f the pulse beats more quickly ; J the appetite is stimu- 

 lated ; * and a surexcitation of the kidneys | and the sexual 

 organs ensues ; A the individual as a rule becomes thinner ; Q the 

 liver tends to increase in size, which is perhaps the cause of a 

 certain sallowness of skin ; J and in females menstruation is often 



* This general subject is somewhat technically discussed in Revue d'Anthropologie, new 

 series, ii, p. 135. 



f Jousset, op. cit., p. 160. Also Bulletin de la Societe de Geographic de Paris, 1878, 

 p. 427. 



\ Ibid., p. 197. * Ibid., pp. 208, 211. | Ibid., p. 221. A Ibid., 229. 



Q Ibid., p. 139. Healthy Europeans in the tropics are lighter in weight than the same 

 class at home (Archiv fur pathologische Anatomie, etc., cxix, p. 254). 



J Hirsch, op. cit., iii, p. 388; cf. Peschel, Races of Man, p. 92. 



