Feb., 1920 Bulletin of the Brooklyn Entomological Society 27 



BOOKS. 



Physical Basis of Heredity, by T. H. Morgan ; pp. 1-305, figs. 



1-117. (J. B. Lippincott Co., $2.50.) 



Here we have the third to appear of the series of Monographs 

 on Experimental Biology. Its author's name denotes its authori- 

 tativeness in the field it covers. While we cannot critically dis- 

 cuss its merits from a genetic standpoint, we do, however, bring 

 it favorably to the notice of entomologists. 



This is, presumably, a college text on genetics. It therefore 

 presents the subject matter in a condensed form, so that all who 

 read may obtain an inclusive view of a large topic. Hence, every 

 entomologist who wishes to get a broad insight into his own 

 subject on the biological side should read this work to inform 

 himself as to the present status of the problem of transformism. 



It has, also, a more restricted interest to us students of insects, 

 for many of the forms experimented with are insects of one 

 kind or another, as, for instance, Drosophila, Protenor, Abraxas, 

 Phylloxera, and other forms. Here we see in these not alone 

 the" carrying of characters from one generation to another and its 

 method, but also the origin of races and of incipient species by 

 mutations within the limits of one species or by crossings of 

 nearly related forms within genera. 



It is quite true some may deem that conditions under which 

 these breedings are carried out depart from the normal to such 

 a degree that their evidence does not carry the weight it might. 

 This appears to be a tenable difificulty, but nevertheless, we 

 cannot affirm that given conditions within variable limits are not 

 normal; nor can we in any way except by direct, empirical ex- 

 perimentation determine what these conditions are, nor what 

 combination of them fixes the optimum. And ^further, the 

 adaptability of the organism to its environment and conditions of 

 life is not always evident. We must at least regard these ex- 

 periments as valuable in demonstrating plasticity, even though 

 we cannot fix the norm, and the possibility of the appearance of 

 new forms arising from variable conditions of food, heat, mois- 

 ture, confinement, interbreeding, and the many other fluctuating 

 elements of the problem. 



Owing to increased cost, the Publication Committee has decided to 

 make a charge for authors' separates in excess of the gratis 25. This will 

 be 5c. each for papers of one to four pages, 6c for 5 to 8 pp., 7c. for 9 

 to 12 pp., proportionately for longer. Special covers will be $1.50 for the 

 first fifty. Half tone plates 2c. additional. 



