1899] DR. WILLEY'S RESULTS 225 



cannot be dealt with here, especially as they are more fully stated elsewhere. 

 He restates his former well-known conclusion of the homology of the vertebrate 

 thymus with the branchial tongue-bars of Enteropneusta, and further finds the 

 homologue of the endostyle in the parabranchial ridges, paired ciliated tracts 

 which pass forwards to unite with the epibranchial band. This suggestion 

 may be further compared with Garstang's comparison of the echinoderm ad-oral 

 band with the endostyle. 



Enough has here been said to show the value of Dr. Willey's contribution. 



The third memoir is by Mr. Shipley, who takes the occasion to give a 

 systematic revision of the groups of Echiurids. Bonellia viridis and four species 

 of Thalassema are comprised in Dr. Willey's collection. The author gives a 

 useful summary of the most valuable specific characters, of which the number of 

 nephridia and the enumeration of muscle bundles appear the most important. 

 The five genera, Bonellia, Echiurus, Hamingia, Saccosoma, and Thalassema, are 

 dealt with. 



From these brief remarks it will be noted that Part III. of the " Zoological 

 Results " is full of interest alike to the morphologist and the systematist, and 

 the author is to be congratulated upon his own labours and upon the able 

 assistance which he has obtained. A. T. M. 



REASONING MADE SIMPLE. 



The Psychology of Reasoning, based on Experimental Researches in 

 Hypnotism. By Dr. Alfred Binet. Translated by A. G. Whyte, 

 B.Sc. 8vo, pp. 191. Chicago: The Open Court Publishing Company, 

 1899. Price 3s. 6d. 



Dr. Alfred Binet's name is well known in association with that of Dr. 

 Charles Fere (placed on the dedication page of this little book), to all who are 

 interested in the phenomena of hypnotism. He here makes these phenomena 

 throw such light as they can on the psychology of reasoning. His treatment 

 has the advantage of perfect lucidity and of a simplicity which is, we venture 

 to think, delusively alluring. 



Reasoning is not regarded by Dr. Binet as a specialisation of conscious 

 activity, and a differentiation only reached at a late stage of mental evolution, 

 but rather as the general form of all psychical life. " To sum up," Ave are told, 

 " all forms of mental activity are reducible to a single one — reasoning." " Three 

 images which succeed each other, the first evoking the second by resemblance, 

 and the second suggesting the third by contiguity — that is reasoning. Submit 

 any reasoning to analysis, and you will find nothing else at the bottom of the 

 crucible. But it would be an error to believe that this process belongs specially 

 to reasoning. Far from it. We meet with it in all intellectual operations ; it 

 is the single theme upon which nature has embroidered the infinite variations 

 of our thought." When a three-day-old chick avoids a cinnabar caterpillar as 

 the result of previous experience of like objects, we have the three successive 

 images ; this caterpillar evoking images of certain others by resemblance, and 

 these others suggesting the nastiness which was unpleasantly contiguous. 

 Changing for convenience the order of formulation, and leaving out one little 

 word, Dr. Binet gives for comparison — 



This is a crystal ; 



All crystals have planes of cleavage • 



This has a plane of cleavage. 



Here, he says in effect, this crystal is on all fours with this caterpillar ; other 

 crystals suggested by resemblance take the place of other caterpillars similarly 

 suggested ; while experience suggests cleavage in the one case just as it sug- 

 gested nastiness in the other. But where does the therefore come in 1 In the 



15 NAT. SC. VOL. XV. NO. 91. 



