438 STELLA B. VINCENT 



which they tested could complete the turn within a one foot 

 fall and some even in six inches. Blindfolded animals did this 

 also but not quite so accurately. They destroyed the semi- 

 circular canals in a few animals and these turned also but not 

 quite so perfectly and they required a greater distance. Animals 

 in "which there was unilateral destruction turned and landed on 

 their feet, but the turn was characteristic, i.e., always away 

 from the lesion. When these animals with one or both canals 

 destroyed were blindfolded the reflex failed. Only a few with 

 one side destroyed succeeded in turning. Ablation of the motor 

 cortex bi- or unilaterally did not abolish it. It occurred even 

 when blindfolded. Decerebration abolished it. The authors 

 conclude that the reflex depends upon excitation derived from 

 the eyes or the semicircular canals, but their evidence was 

 non-conclusive either for or against Sherrington's theory that 

 the muscles predominantly affected are those which antagonize 

 gravity. 



Amphibians. — Howat (12) studied the effect of nicotine on 

 the skin reflexes of frogs. She found that certain spots in the 

 frog's skin differ not only in irritability and reflex action but 

 also in susceptibility to the influence of nicotine. The skin 

 reflexes were affected by much smaller quantities of nicotine 

 than the higher reflexes, e.g., turning over, compensatory and 

 swimming. Small doses of the drug caused a depression of the 

 reflexes and increasing doses brought about a tolerance. 



INSTINCTS 



Birds. — Watson (27), in the Carnegie Institute publications, 

 has an historical and experimental study of homing. There is 

 an excellent critical account of the various theories of homing, 

 a brief summary of such instinctive activities of the noddy and 

 sooty terns as have a bearing on the question, and a record of 

 the experimental homing flights of these same birds in 1910 

 and 1913. Some of these flights covered as great a distance as 

 855 miles. In the same interesting field Cooke (5) has published, 

 in a government bulletin, an account of migration with reference 

 to the weather, the time of day, the distance covered, the routes, 

 the rate of flying, etc. The maps are the most valuable part 

 of this bulletin. They show both the general migration routes on 

 the western continent and the special routes of different species. 



