April 25, 1913] 



SCIENCE 



635 



germination and the second with the appear- 

 ance of the first flower. He believes that de- 

 velopment is controlled during the earlier 

 period mainly by air conditions, especially 

 temperature, and during the second period 

 mainly by soil conditions, especially vcater 

 content. He regards as the limiting factor 

 for growth what he terms " thermotoxy " — the 

 supposed accumulation of injurious products 

 of metabolism caused by high temperatures 

 and aggravated by a deficient water supply. 

 Varietal differences in length of the growth 

 period would indicate corresponding differ- 

 ences in resistance to " thermotoxy." Experi- 

 ments are described which deal with the ef- 

 fect of a high water table in checking root de- 

 velopment and in inducing shedding of the 

 flower buds. This subject is at present much 

 discussed in Egypt in connection with the 

 recognized deterioration of the cotton crop. 



In the field of genetics fluctuation, natural 

 crossing and heredity are treated. Much space 

 is devoted to the application of Mendelian and 

 post-Mendelian principles to cotton hybrids. 

 This discussion, interesting and suggestive 

 though it be, will scarcely inspire the cotton 

 breeder with confidence that his practical 

 problems will be speedily solved by the Men- 

 delists. 



By way of criticism, attention may be called 

 to a certain lack of balance in the space de- 

 voted to different phases of the subject. Thus 

 the morphology of the vegetative organs, 

 which is of great interest agriculturally as 

 well as botanically, receives but scant notice. 

 One reads with astonishment that there is 

 " apparent identity of all the modern varieties 

 of Egyptian cotton in external appearance — 

 for, even when grown side by side, they are 

 scarcely distinguishable." Several of the va- 

 rieties, when grovpn in Arizona from im- 

 ported seed, have proven readily distinguish- 

 able by the characters of the leaves, bracts 

 and bolls. There is also a tendency to put 

 forth rather sweeping generalizations. Such 

 are the assumptions, regarding fluctuation, 

 that in a pure strain it " is the result of 

 slight irregularities in a normally uniform 

 environment " (p. 89) and that " physiology 



explains it" (p. 90). It is also not very clear 

 to the uninitiated why transmitting power 

 " is not a mysterious vital function " merely 

 because it " can be reduced to formulse." Sev- 

 eral of the text figures are left without satis- 

 factory explanation, either in the legends or 

 in the text, and the reader would be saved 

 time and trouble if the pages were cited in 

 referring to the figures. 



Nevertheless this little volume can not fail 

 to be helpful and suggestive to all investiga- 

 tors of the cotton plant and not its least valu- 

 able mission is to show some of the ways by 

 which scientific investigation of a crop plant 

 may be brought to bear in improving agri- 

 cultural practise. 



T. H. K. 



Naturwissenschaftliche Studien am Toten 

 Meer und im Jordantal. Von Professor Dr. 

 Max Blanckenhorn. Berlin. 478 pages 

 with geographical map and table. 

 Students of the geology of Palestine prob- 

 ably owe more to Dr. Max Blanckenhorn than 

 to any other one author. The present volume 

 is an account of his last expedition undertaken 

 in 1908 at the request of the Turkish govern- 

 ment. The ex-sultan, Abdul Hamid II., ap- 

 parently desired to discover mineral wealth in 

 the valley of the Jordan River and Dead Sea, 

 which is his private property. Dr. Blaeken- 

 horn, however, wisely insisted that the exx)€- 

 dition should be primarily scientific, and not 

 economic. The results justify his position, 

 for Palestine is very poor in mineral wealth. 

 Pure science, however, did not satisfy the 

 Turkish government which still, in spite of 

 repeated promises, owes Dr. Blanckenhorn 

 twenty-five hundred dollars for expenses in- 

 curred at their request. 



Dr. Blanckenhorn's work divides itself into 

 three closely related parts, economic, geologic 

 and physiographic. In respect to the first two 

 we accept his results without question, but as 

 to the third there is some doubt. Inasmuch 

 as the geological formations of Palestine are 

 almost entirely cretaceous, little mineral 

 wealth is to be expected. The salt deposits of 

 Jebel Usdum at the south end of the Dead 



