Literary Notices. liii 



obligation, an obligation which the present writer gladly acknowledges, 

 as he has found many of these contrivances very useful in his own la- 

 boratory. 



The leading article in the third volume is by Dr. C. E. Seashore 

 on " Measurements of Illusions and Hallucinations in Normal Life." 

 This is a paper of vital importance to every laboratory psychologist, 

 for the conclusions reached have an important application to some of 

 the most fundamental methods of the experimental method. By an 

 elaborate series of experiments, the details of which must be sought in 

 the original, Dr. Seashore has shown the truly surprising ease and viv- 

 idness with which it is possible to evoke illusions and hallucinations in 

 every department of sense and that too in experienced psychologists 

 and under the conditions of rigid control of the laboratory experiment. 

 The hallucinations here described are evoked mainly in response to 

 forced expectant attention and it is shown that this is one of the fac- 

 tors which must be guarded against in all experiments on liminal differ- 

 ences. Certain experiments on discrimination and many other classes 

 of laboratory studies will receive cautionary hints from this paper. 



The " Studies of Fatigue " by John H. Moore take up the effect 

 of fatigue on binocular estimate of depth, the effect of fatigue on mon- 

 ocular estimate of depth, the effect of fatigue on the time of monocular 

 accommodation, and the effect of fatigue on the maxium rate of volun- 

 tary movement. Several j)oints of practical pedagogical interest are 

 developed. For instance, several of these experiments on the estima- 

 tion of depth by means of the muscles of accommodation and con- 

 vergence emphasize the extreme danger to the eyes of carrying on for 

 long periods of time such accommodation as must be employed in 

 copying unfamiliar subjects from the blackboard to the paper or slate, as 

 is so often done even in the lower grades of our schools. c. j, H. 



The Embryology of the Medulla of the Rabbit' 



In this paper Dr. Dexter has followed the development of the 

 medulla of the rabbit in order to make comparisons with that of man 

 as worked out by His. He finds several differences, some of them 

 quite unexpected. The tractus solitarius is buried more deeply in the 

 medulla as development progresses by the migration, as the author sup- 

 poses, of scattered ectodermal elements lying on the border of the me- 

 dullary wall and " Randschlier," and not by the formation of a rhom- 



'Fkankmn Dkxter, M.D. A Contribution to the Morphology of the Me- 

 dulla Oblongata of the Rabbit. Privately printed from the Archiv fiir Anatomic 

 und Physiologie. Boston, 1896. 



