812 



SCIENCE. 



[N. S. Vol. XXIII. No. 595. 



upon the more extended and critical study 

 of plants and all their variable forms— in 

 the field. Just as the origin of plant spe- 

 cies does not depend solely upon hybridiza- 

 tion, or mutation, or isolation, but upon all 

 these agencies working together, so the sal- 

 vation of botanical science does not rest in 

 systematic botany, or in ecology, or in 

 physiology or in morphology, but in the 

 closer association of all these, and in more 

 perfect cooperation between them. 



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The circles in this figure may be taken 

 as representing groups of individual plants, 

 or mountain tops, or meadows, or swamps, 

 or islands in the sea, etc. For instance, 

 A, B and C may represent well-recognized 

 'species' of plants where they are most at 

 home, i. e., the 'mother group.' Outlying 

 groups in the different directions — a hun- 

 dred feet or a hiuidred miles distant — vary 

 from the typical form or the dominant 

 form. At G two groups approach each 

 other and hybrids may occur there, though 

 the occurrence of these hybrids would not 

 necessarily bring into question the utter 

 specific distinctness of A and B unless some 

 superficial investigator should, through 

 lack of sufficient data, erroneously call them 

 'intermediate forms.' The younger group, 

 D, evidently related to the others, perhaps 

 arose by hybridization or mutation, its per- 

 petuation perhaps due to sudden isolation. 

 J may represent a descending ridge from 

 the mountain at A. The groups I and E 

 might be very different, and considered 



specifically distinct if judged by hurried 

 collecting, whereas careful work up the 

 respective canons towards the summit or 

 center of distribution at C would establish 

 their relationship. So changed may D 

 have become as to make its relations to B 

 and C, its nearest relatives, wholly prob- 

 lematical, and an absence of individuals in 

 intervening territory may prevent its ref- 

 erence to either except perhaps after ex- 

 perimental work. Evidently there may be 

 actually in the field a thousand degrees of 

 relationship, and in a systematic botany 

 . which shall mirror to some extent actual 

 existing conditions, the terms 'variety' and 

 'race' have a scarcely intelligible place. 

 The term 'form,' however, may well be in 

 constant use. I do not know of any Amer- 

 ican species being charted in the above 

 manner. Such work is rendered difficult 

 by the superposition of hundreds of species 

 —it will require a good eye, patience and 

 steadfastness to a single object. 



C. F. Baker. 

 EsTACioiT Aqkon6mioa, 



Santiago de las Vegas, Cuba. 



SCIENTIFIC BOOKS. 

 Experimental Electrochemistry. By N. Mon- 

 roe Hopkins, Ph.D., Assistant Professor of 

 Chemistry in the George Washington Uni- 

 versity. New York, D. Van Nostrand 

 Company. 1905. 



This is an interesting book. Its author has 

 so arranged it that it may be read previous to 

 performing any experimental work, giving 

 thereby an excellent picture of the historical 

 development of electrochemistry. Any per- 

 son adopting this plan wiU find himself in 

 possession of many most interesting facts and 

 helpful ideas, which are sure to prove in- 

 centives to carrying forward experimentation 

 in this very attractive field of chemical sci- 

 ence. Here is a thought which every student 

 who thinks at all of electrochemistry should 

 carefully ponder: 



Electrochemical operations are essentially chem- 

 ical and based upon purely chemical changes, and 



