564 



SCIENCE. 



[N. S. Vol. XII. No. 302. 



tures ' delivered at ' Woods Hell, but contains 

 in addition to sucli lectures essaj'S written es- 

 pecially for the volume by persons not in af 

 tendance at the session, but in sympathy with 

 the work of the laboratory. At present, then 

 the volume may be said to be representative 

 of American biologj'. In its scope the volume 

 is unique ; its contents are addressed by nat- 

 uralists to a general biological audience — an 

 audience which demands at once that the au- 

 thor shall have something worth while to say 

 and that he shall say it in an intelligible man- 

 ner, free from the burden of a very special and 

 technical nomenclature, while scientific rather 

 than popular. 



There are sixteen lectures in this volume, of 

 which four are botanical. D. H. Campbell 

 treats of the ' Evolution of the Sporophyte ' ; 

 D. P. Penhallow of the ' Nature of the Evi- 

 dence exhibited by Fossil Plants ' ; and D. T. 

 MacDougal has two papers on the ' Influence of 

 Vertical Air Currents upon Distribution' and on 

 ' Mycorrhizas,' respectively. Then follow three 

 papers of general psychological interest ; two by 

 Edward Thorndike on 'Instinct ' and ' The Asso- 

 ciative Processes in Animals,' based on his own 

 illuminating investigations, and one by H. S. 

 Jennings giving a resum6 of his brilliant results 

 on the ' Reactions of Unicellular Orgaaisms. ' 

 C. H. Eigenmann contributes a paper on ' The 

 Blind Fishes' and A. Hyatt, a 30 page paper 

 on ' Some Governing Factors usually neglected 

 in Biological Investigations,' which calls for an 

 appreciation of meta-genetic (gerontic) stages 

 in ontogeny, defends the ' law of tachj'genesis 

 or accelerated development ' and argues for the 

 memory theory of heredity. A. G. Mayer dis- 

 cusses the ontogenesis and phylogenetic signifi- 

 cance of color in Lepidoptera. A. Mathews 

 analyzes the diflferent methods of animal secre- 

 tions and combats the theory of special secre- 

 tory nerves. T. H. Morgan discusses some old 

 and new interpretations of regeneration. G. N. 

 Calkins draws important general cytological 

 conclusions from the varied forms of nuclear 

 division in protozoa. C. M. Child after giving 

 his researches on spiral cleavage concludes that 

 it is the organism — the individual — which is the 

 unit and not the cell. The reviewer writes of 

 the aims of the quantitative study of variation 



and J. Loeb tells of his success in getting un- 

 fertilized eggs of sea urchins to develop into 

 larvffi under the action of magnesium chloride. 

 The mere enumeration of these subjects indi- 

 cates that biological investigation in this coun- 

 try to-day occupies a broad field. 



C. B. Davenpoet. 



A Manual of Elementary Practical Physics. By 



Julius Hoetvet, B.S. Minneapolis, H. W. 



"Wilson. 1900. 



During the last few years which have been 

 signalized by the great extension of laboratory 

 instruction in physics in the secondary schools 

 of this country, so many new text-books of 

 physics have been published that one can 

 scarcely treat a new-comer without preju- 

 dice. These books must avoid a Scylla and 

 Charybdis quite as dangerous as those which 

 threatened Ulysses. On the one hand they fail 

 by trying to be too general, applicable to too 

 many cases, the school, the college and even 

 the university ; on the other hand they repre- 

 sent some particular, special course which 

 their author has worked up, too often with 

 some personal hobby for certain things. In 

 this last class fall those courses which are de- 

 signed as an entrance requirement for some 

 college, and which are too much elementary 

 mechanics and too little physics. 



Mr. Hortvet has recognized that it is his. 

 duty to give his students the best possible course 

 in general physics which they can utilize, with- 

 out leaving it to a possible college course to 

 give the real fundamentals. It is the business 

 of the college to coordinate its work upon that 

 of the high school, provided only that the high 

 school is doing the right work and doing it 

 well. Mr. Hortvet understands that his labora- 

 tories are neither kindergartens nor research 

 laboratories. 



Many teachers with the catch words of in- 

 tensive, rather than extensive, fail to appre- 

 hend the real meaning of the terms, and are 

 so extensive in their desire to be intensive that 

 the scholar is lost in a mass of details and gets 

 no fundamental principles. These teachers feel 

 that they could not touch the subject of refrac- 

 tion of light without including anomalous dis- 

 persion and double refraction, and hence dawdle 



