408 STELLA B. VINCENT 



"(3) Apparent reaction to tones are most probably made to 

 accompanying noises. 



"(4) If after all there is a sensitivity to tonal stimuli as here 

 tested, then, for the rat, tones and noises are very different 

 classes of stimuli." 



Miss Barber's work (3), from the same laboratory, was con- 

 cerned primarily with the accuracy of the localization of sound 

 and the relation of the intensity, absolute and relative, to the 

 accuracy of this response. The apparatus was an octagonal 

 shaped box whose floor was divided into 32 sections. This box 

 stood on a table surrounded by a stimulus screen and the opera- 

 tor was invisible. The stimuli were tapping with an instrument 

 whose predominant pitch was 256 dv, a tuning fork and an organ 

 pipe of the same pitch, hissing through the teeth and tapping 

 with a lead pencil. A regular order of presentations was fol- 

 lowed in which each of the 32 sections of the box was given once 

 every four days. There was an attempt made to control kinaes- 

 thetic, olfactory and visual clues. Only seven rats were used. 



The writer while realizing the defects of the apparatus believes 



that the rat is able to localize noise with an average accuracy 



of two to four inches under the conditions of the experiment. 



She thinks that the auditory factor which in general determined 



the accuracy of the response was probably the relative intensity 



of the sound to the two ears. ' The rats were not only unable 



to localize pure tones from tuning forks but absolutely ignored 



them." 



CHEMICAL SENSITIVITY 



Fish. — Wells, (36) using Shelford's apparatus and methods, 

 reports some experiments which deal with the reaction of fresh 

 water fishes to acidity and alkalinity. He finds that they select 

 a slight acidity in a gradient when the other possible choices 

 are neutrality and alkalinity but choose a slight alkalinity in 

 preference to neutrality. The writer calls attention to the fact 

 that the distribution of plankton in the lakes of Wisconsin and 

 New York shows a very interesting correlation with the chem- 

 ical reactions of the water of the lakes. 



An experimental study of the movements of herring and 

 marine fishes was undertaken by Shelf ord and Powers (25) at 

 the Puget Sound Marine Station. This study is important 

 because we do not know enough of the chemical condition of 



