November 15, 1895.] 



SCIENCE. 



667 



might be purely mechanical and analogous to 

 the control of one vibrating body by another, 

 the medium of control in this case being the 

 sensitiveness of one insect to the stridulations of 

 another. But the fact that they often start all 

 at once seems to bar out this hypothesis, and, 

 indeed, is a fact difficult to account for in any 

 way. 



As to the pitch, it certainly seems as if one 

 ' orchestra ' were from a semitone to a tone re- 

 moved from the other, but, as Mr. Scudder sug- 

 gests, this may be only apparent. In case it is 

 real, however, may it not be due to the falling 

 into beat of each insect with those to whose 

 stridulation it is most sensitive — namely, those 

 that produce sounds approximating to its own 

 in pitch? Arthur P. Bostwick. 



New York, November 5th. 



THE SCIENCE OF MENTATION. 



Editor of Science : Some time since a refer- 

 ence was made in Science to a paper published 

 with the above title in the Monist for July. 

 The author was reported to have studied by ex- 

 perimental methods the development of certain 

 forms of mentation in dogs. As ■ I have been 

 greatly interested in the subject of comparative 

 psychology for years, and have myself been de- 

 voting much time to the study of the psychic 

 development of animals from bii'th onward with 

 investigation of the contemporaneous changes 

 of a physical kind especially in the brain, I 

 looked up the article referred to, written by 

 Mr. Elmer Gates. Many of the statements and 

 conclusions are of so remarkable a character 

 that I should be glad to get further information, 

 as would, no doubt, others also. We are told 

 that seven shepherd puppies were confined in a 

 completely darkened room for nine months ; 

 that the mother was permitted to go in and out ; 

 but we are not informed as to whether the 

 mother was admitted for the sole purpose of 

 suckling the puppies, though this is the natural 

 inference. Now, if a dam is capable of supply- 

 ing seven puppies at nine months of age with 

 all the nourishment they require, as one speci- 

 ally interested in dogs and who has for years 

 made a special study of these animals and bred 

 them extensively, I should like to know the 

 facts ; for nothing of like kind is, so far as I am 



aware, on record, and on the face of it I should 

 doubt the possibility of such a thing. I see no 

 necessity for any such drain on the dam, yet 

 Mr. Gate's paper leaves the matter in doubt. 



Again, though the most sweeping conclusions 

 are drawn as results both positive and negative, 

 following functional use and disuse, of certain 

 portions of the organism, and though these ex- 

 periments stand almost or quite alone, but mea- 

 gre details are given either of the experiments or 

 the anatomical appearances, and not a single 

 illustration either diagrammatic or other accom- 

 panies the paper, nor is there any intimation that 

 such details or illustrations have been or are to 

 be published elsewhere. I should like to point 

 out that such work is of but little use to scientiiic 

 men in its present form, for at best it is only 

 suggestive, not demonstrative. It is to be 

 hoped that if Mr. Elmer Gates can furnish the 

 details and illustrations necessary to meet sci- 

 entific requirements he will lose no time in doing 

 so, as, if his experiments, etc., are probable and 

 his conclusions correct, they are not only of 

 great scientific interest but of much practical 

 importance to educationists and others. Mr. 

 Gates' paper abounds in very stimulating ' men- 

 tation,' and much of it seems to fit very natur- 

 ally into my own mental moulds. In asking 

 for more details I think that I am writing in the 

 interests of a large class of scientists and others. 

 Wesley Mills. 



Physiological Laboratory, 



McGiLL University, Montreal. 



inverted image once more. 

 If Prof Woodworth (see Science, October 

 25, p. 555) will look into my little volume on 

 Sight, pp. 87 and 88, he will find described and 

 explained not only the phenomena he refers to, 

 but all his experiments with the lids. I have 

 been familiar with the phenomena all my life, 

 but first described and explained it in 1871 (see 

 Phil. Mag., Vol. LXI., p. 266, 1871). I after- 

 wards discovered that it had been previously 

 explained by Priestley. It is not due to imper- 

 fect accommodation, as Prof. Cattell thinks, but 

 to refraction by the concave watery meniscus be- 

 tiveen the two lids and the surface of the cornea. 

 The following figure will explain itself and the 

 phenomena in question. The central ray c c' 



