BOOK REVIEWS. 



441 



chemical agents, thermal and electrical excitements, &c. The plant 

 used was the sensitive Mimosa pudica. Besides quantitative move- 

 ments, time relations were investigated ; thus the normal maximum 

 rate of movement was found to be 50 mm. per second. Temperature 

 enhances the rate. 



" By means of electric response, it may be shown that every plant, 

 and every organ of the plant, is sensitive and responds to stimulation 

 by a definite electric change. The sensitiveness of Mimosa to electrical 

 stimulus is high, and may even exceed that of a human subject." 



Dr. Bose shows also the " Influence of Load " and the " Work 

 performed by the Plant : " that the recording response is greater in 

 proportion to the weight, and that if W 1} W 2 , W 3 indicate increasing 

 weights, and h 1} h 2 h 3 the corresponding heights of response, then 

 W Y hj < W 2 h 2 > W 3 h 3 ; "in other words, the work performed is 

 increased under enhanced load and increasing tension." 



Though not alluded to, this corresponds with the visible effects ; 

 for if a young petiole be weighted, there will be found a considerable 

 increase in the amount of mechanical tissues when full grown, over 

 that of a normal petiole, which only supports the blade. 



Space will not allow a detailed description of the book ; but the 

 above will reveal the importance of this work to all interested in vital 

 phenomena. 



" Plants and their Uses : An Introduction to Botany." By 

 F. L. Sargent. With numerous illustrations. 8vo., 610 pp. (Holt, 

 New York, 1913.) $1.25. 



This is an excellent treatise on useful plants, with an abundance 

 of illustrations. After a preliminary chapter on The Study of Plants, 

 the author deals with cereals, various food plants, flavouring, and 

 medicinal and industrial plants. 



Chaptei VII. deals with Classification, &c, so as to introduce 

 typical natural orders with useful plants. 



Now we must turn to what seems to us to be quite superfluous 

 and troublesome. Pp. 404-427 contain formulae of some 270 or 

 more genera indicated by letters and symbols. Thus for example : 



Clematis. — CE 00, o Eie2 -f T Cj < co Ei G-N. 

 W T hen we remember that there are four sepals, no corolla, 00 stamens, 

 co carpels ; all parts free ; we do not see the use of the above. 



Discussing different views as to the origin of species, the author 

 offers a new factor, " choice." " A living thing is active as well as 

 passive. The idea is thus suggested that organic evolution may 

 have as its controlling factor some power of choice, essentially like 

 our own, residing in all living organisms — a will as truly free." 



The fallacy underlying this idea is that the author does not appear 

 to perceive the differences between " automatism " and " free will." 

 It is accepted that man alone has the latter and can " choose," and 

 that no other being can do this, but acts automatically under the 



VOL, XXXIX. 2 C 



