RECENT ADVANCES IN SCIENCE 225 



ment of light is heralded by a paper by MacDougal and Spoehr, 

 " The Measurement of Light in some of its more Important 

 Physiological Aspects" (Science, 45, 616-18, 191 7), in which 

 some preliminary measurements of light intensity in the blue- 

 violet region of the spectrum is carried out by means of the 

 photo-electric cell originally suggested by Elster and Gestel. 



With regard to the products of assimilation, Kylin, " Zur 

 Kenntnis der wasserloslichen Kohlenhydrate der Laubblatten " 

 (Hoppe-Seyler's Zeitsch. physiol. Chem. 101, 77-88, 191 8), has 

 published the result of some analyses in respect to carbo- 

 hydrates of foliage leaves of a number of species, including 

 Convallaria majalis, Gentiana brevidens, Tillia europcea, and 

 Taraxacum. The leaves were gathered at midday during 

 May and June. He reports that, broadly speaking, the amount 

 of glucose in the leaves varies inversely with the amount of 

 starch, but Convallaria majalis contained little of both. Al- 

 though sugar-leaves as a rule contain more sucrose than starch 

 leaves, Gentiana brevidens, which is a sugar leaf, contains no 

 sucrose, while the lime (a starch form) contains sucrose in 

 considerable quantity. With regard to these results it may be 

 pointed out that the methods of analysis are considerably 

 less developed than those employed by Davis, Daish, and 

 Sawyer, or even those of Gast, which were reported upon in 

 these pages a year ago. 



Finally may be mentioned a paper by Lakon, " tJber die 

 Bedingungen der Heterophyllie bei Petroselinum sativum 

 (HorTm.) " (Flora, 10, 34-51, 191 7), in which one of the most 

 interesting aspects of carbon assimilation is dealt with — the 

 relation of this process to the life of the plant as whole. 



PALEOBOTANY IN 1917. By Marie C. Stopes, D.Sc, Ph.D., 



University College, London. 



With the exception of a large volume by Prof. Seward 

 (vol. iii. Fossil Plants) there appears to be nothing of any size 

 published in Paleobotany in 191 7, although there are three 

 or four papers of particular interest and importance. 



Again this year there is a sad depletion of the ranks of 

 the experts in the science of Paleobotany, and death has taken 

 at least three whose names will long remain in the memory of 

 students of the subject. 



The obituary of Clement Reid, who died in 191 6, appeared 



