November 26, 1920] 



SCIENCE 



517 



Cornell: Walter Norton Hess, "Studies on the 

 Lampyridse. " Clarence Hamilton Kennedy, 

 "Study of the phylogeny of the Zygoptera. " 

 Pred Waldorf Steward, "Development of the 

 cranial sympathetic ganglia in the rat." Benja- 

 min Percy Young, ' ' Attachment of the abdomen 

 to the thorax among Diptera. ' ' Laura Florence, 

 "Hog louse, Scematopinus suis, Linn6: its biol- 

 ogy, anatomy and histology." Walter Housley 

 Wellhouse, "Insect fauna of the genus Cra- 

 tcegus. ' ' 



George Washington: Benjamin Schwartz, "He- 

 motoxins from parasitic forms." Prank Alex- 

 ander Wetmore, "Body temperature of birds." 

 Thomas Elliott Snyder, ' ' Colonizing termites. ' ' 



Harvard: Vasil Obreshkove, "Photic reactions of 

 tadpoles in relation to the Bunsen-Roseoe Law. ' ' 

 James Montrose Duncan Olmsted, "Experi- 

 ments on the olfactory and gustatory organs of 

 Amiurus nehulosus (Lesueur)." Herbert Green- 

 leaf Coar, ' ' Shell of Balanus eiurnus. ' ' Wil- 

 liam Norton Barrows, "Modifications and de- 

 velopment of the arachnid palpal claw, with 

 especial reference to spiders." Leslie Clarence 

 Dunn, ' ' Linked genes in mammals. ' ' Alfred 

 Charles Kinsey, "Studies of gall- wasps (Cyni- 

 pidce hymenoptera)." 



Illinois: Hachiro Yuasa, "Classification of the 

 larvsB of Tenthredinoidea. ' ' 



Indiana: William Marion Goldsmith, "Compara- 

 tive study of the chromosomes of the tiger 

 beetles (Cicindelidce) ." William Eay Allen, 

 "Studies of the biology of freshwater mussels." 



Iowa State: Gertrude Van Wagenen, "Coral 

 Mussa fragilis, and its development." 



Johns Hopkins: Bessie Noyes, "Experimental 

 studies on the life history of a rotifer repro- 

 ducing parthenogenetically (Proales decipiens) ." 

 Hoyt Stilson Hopkins, "Conditions for conju- 

 gation in diverse races of Paramcecium." 



Kansas: Paul Bowen Lawson, " CicadillidES of 

 Kansas. ' ' 



Michigan: Walter Norman Koelz, "Coregonine 

 fishes of Lake Huron. ' ' 



Missouri: Erwin Ellis Nelson, "Chemical compo- 

 sition of the ovaries and skeletal muscle of the 

 fresh water gar, Lepidosteus." 



Pennsylvania: Joseph Hall Bodine, "Factors 

 influencing the water content and the rate of 

 metabolism of certain Orthoptera. " 



Princeton: Wilbur Willis Swingle, "Germ-cell 

 cycle of Anurans. I. The male sexual cycle of 

 Mana catesfrava. ' ' Elmer Lentz Shaffer, 



"Germ-cells of Cicada septemdecim (Homop- 

 tera)." 



Wisconsin: Bert Cunningham, "Some studies in 

 the natural history and early development of 

 Chrysemys cinerea." George Holman Bishop, 

 Title for thesis not given. Archie Evans Cole, 

 Title for thesis not given. 



Yale: Harry Hay ward Charlton, "Spermato- 

 genesis of Lepisma domestica." Euth B. How- 

 land, ' ' Experiments on the effect of removal of 

 the pronephros of Amblystoma punctaty/m." 

 Callie Hull, 

 Technical Assistant 

 Research Ineormation Service, 

 National Research Council 



SPECIAL ARTICLES 



A METHOD OF STUDYING THE ABSORPTION- 

 TRANSPIRATION RATIO IN NUTRIENT 

 MEDIA 



Several writers have shown that the water 

 content of plants varies with the hour of the 

 day. This variation is of course due to dif- 

 ferences in the rates of water entrance and 

 exit. Wilting takes place when the ratio of 

 the rate of entrance to the rate of exit is less 

 than unity whether caused hy excessive trans- 

 piration or by a decrease in root absorption. 

 These two plant processes may easily be stud- 

 ied as a laboratory exercise in plant physiology 

 by using water culture plants exposed to dif- 

 ferent environmental conditions or placed in 

 solutions of different osmotic pressures. The 

 following experiment will serve to illustrate 

 the manner in which changes in the strength 

 of solutions affect the ratio of absorption to 

 transpiration. The method here described is 

 practically the same as one used by the writer 

 in a series of experiments reported by Living- 

 ston.^ 



The roots of a tomato plant were passed 

 through a hole in the rubber stopper of a large 

 mouth bottle of about 600 c.c. capacity. A 

 water-tight seal of chewing gum was made 

 around the stem of the plant; a 2 c.c. pipette, 

 graduated to 1/20 c.c. and a thermometer were 

 inserted into the bottle through the stopper. 



1 Livingston, B. E., "Incipient Drying and 

 Temporary and Permanent WOting of Plants, as 

 Belated to External and Internal Conditions, ' ' 

 Johns Hopkins Univ. Oir., March, 1917, pp. 176-82. 



