426 JOHN B. WATSON 



Breed's (4) paper is concerned more with the modifiability of 

 reactions than with the function of vision as such. Neverthe- 

 less experiments were made upon the color, form and size per- 

 ception of the chick. The evidence for color vision, while ob- 

 tained incidentally, is believed by the author to support the 

 view that color quality as well as intensity is a determining 

 factor in the chick's response. The chicks seem to be able to 

 respond selectively to one of two objects of different size. The 

 form tests gave purely negative results. In a note on page 57 

 the author states, however, that a chick acquired the circle- 

 square habit when the experiments were conducted in the dark 

 room. One interesting methodological point is brought out in 

 Breed's work. Chicks will peck in the dark. The work of Hess 

 and of Katz and Revesz on vision in the chick is based upon the 

 assumption that the chick will not peck at what it cannot see. 

 The work which the reviewer has carried out upon the limits of 

 the spectrum in chicks this summer wholly confirms Breed's 

 findings in this respect. 



Mammals. Minkowski (17) reports in a long and closely 

 articulated paper the results of extended tests upon the locali- 

 zation of the visual centers in the dog. The methods of testing 

 the visual field in normal dogs and of locating the visual defects 

 in the dogs after cortical operation are described as follows. 

 The dog sat with one eye securely bandaged. A piece of meat 

 was then held by a slender rod or with forceps before the other 

 eye at a distance of about 10 cm. This gave a reasonably steady 

 fixation. A perimeter was then drawn forward in such a posi- 

 tion that the bit of food occupied its center. A second bit of 

 food was then drawn along one arm of the perimeter until the 

 dog noticed the food and snapped at it. By rotating the peri- 

 meter in the usual way the following field was mapped out: 



Upper vertical 6o°-65° 



Lower vertical S°°-SS° 



Outer horizontal 8o°-9o° 



Inner horizontal 3°°-35° 



The ''Kreisfuhrungsmethode" was employed in a supplementary 

 way. This consisted in moving the bit of food before both eyes 

 of the dog in circles so that the image had to fall at some time 

 upon the upper, lower, inner and outer portions of the retina. 



