THE CURVES OF LIFE: A CRITICISM 401 



very regular and beautiful formation. In another very interesting 

 section details are given of the extraordinary phenomena exhi- 

 bited by climbing plants, which twine spirally round any 

 support, preferably upright ones. In this connection Mr. Cook 

 discusses plant-intelligence, and quotes a passage from Sir 

 Francis Darwin, who states that " a plant has memory in 

 Hering's and S. Butler's sense of the word, according to which 

 memory and inheritance are different aspects of the same quality 

 of living things. Thus, in the movements of plants . . . the 

 individual acts by that unconscious memory we call inheritance." 

 This view, which has been mentioned above in connection with 

 shell-formation, seems to be the only one which throws any 

 light on these special forms and growths of living things. 



Mr. Cook has given a great deal of attention to the spiral 

 formation in the horns of animals, and has collected some 

 remarkable facts, but this subject does not seem to have any 

 close connection with the immediate subject and object of the 

 book. The spirals of horns require to be reduced to plane 

 spirals before one can compare their characters, as their general 

 form is too diverse and irregular. 



Of the spiral formations in the body a somewhat short 

 account is given, and Prof. Dixon's beautiful work on the bones 

 is laid under contribution. It is a pity that the work on the 

 extremely complex spiral arrangement of the trabeculse in the 

 femur and long bones is not more fully treated ; but measure- 

 ments, or anything but general statements, must be very difficult 

 or impossible in such a case. The cochlea is mentioned in such 

 close connection with the femur that it would be better to point 

 out that the function of the spiral arrangement here is quite 

 different to that in the femur, this ensuring strength in the 

 one case and extension in the other. Many other parts of the 

 animal body show a spiral arrangement, such as the umbilical 

 cord, the cystic duct, sweat ducts, muscle-fibres around 

 arterioles, the muscular fibres of the heart, wings of birds and 

 insects, and intestines of certain animals and birds. Some of 

 these are very complicated, and it must be a long time before 

 they can be classified and compared. In some of these cases the 

 spiral arrangement is of advantage from a mechanical or func- 

 tional point of view, but in many instances its significance is 

 uncertain or unknown. 



There is a very suggestive chapter on right- and left- 

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