420 



SCIENCE 



[N. S. Vol. XLVII. No. 1217 



tion of magnesium sulphate in tetanus; (6) the pos- 

 sible danger of intravenous injection of mag- 

 nesium sulphate; (c) The antagonistic and curative 

 action of calcium salts in these cases, by 8. J. 

 Meltzer. 



The Liberty field hospital ward. Designed on 

 the unit construction plan. Portable. Adapted to 

 American overseas summer and winter service (mo- 

 tion pictures), by Henry Fairfield Osborn. 



The war and medical research (illustrated), by 

 Simon Flexner. . 



Afternoon Session 



Conformal geometry, by Edward Kasner. 



Magnestism by rotation (illustrated), by S. J. 

 Earnett (by invitation. Comstock prize recipient) . 



On the correction of optical surfaces, by A. A. 

 Michelson. 



Some recent observations of the brighter nebulffi 

 (iUustrated) , by W. W. CampbeU. 



Physical researches for the war, by E. A. Milli- 

 kan. 



Evening Session 



First William EUery Hale Lecture, by John C. 

 Merriam, professor of paleontology. University of 

 California. Subject: The beginnings of human 

 history from the geologic record. (Open to the 

 public.) 



TUESDAY, APKIL 23 



Morning Session 



Notes on isotopic lead, by F. W. Clarke. 



The physico-chemical properties of gluten, by 

 Lawrence J. Henderson (introduced by Raymond 

 Pearl). 



Correlation of the tertiary formations of the 

 southeastern United States, Central America and 

 the West Indies, by Thomas Wayland Vaughan 

 (introduced by David White). 



Coast survey charts and fringing reefs of the 

 Philippine Islands (illustrated), by W. M. Davis. 



Kecent researches on the skeletal adaptations and 

 modes of locomotion of the Sauropod Dinosaurs 

 (illustrated), by Henry Fairfield Osborn and Wil- 

 liam K. Gregory. 



Some additional data on the Cambrian Trilobites 

 (illustrated), by Charles D. Walcott. 



The development of governmental regulations 

 during the world war, by C. E. Van Hise. 



Afternoon Session 



The big bears of North America, by C. Hart 

 Merriam. 



The growth of the Pribilof fur-seal herd be- 

 tween 1912 and 1917 (illustrated), by G. H. 

 Parker. 



A comparison of the growth changes in the ner- 

 vous system of the rat with the corresponding 

 changes in man (illustrated) , by Henry H. Donald- 

 son. 



Measuring the mental strength of an army (il- 

 lustrated), by Eobert M. Yerkes (by invitation). 



Second William EUery Hale Lecture, by John C. 

 Merriam, professor of paleontology, University of 

 California. Subject: The beginnings of human his- 

 tory from the geologic record. 



SPECIAL ARTICLES 



A SIMPLE METHOD OF MEASURING 

 PHOTOSYNTHESISi 



In coll^b&ration with Loeb^ one of us ob- 

 served tha;t certain marine algae when exposed 

 to sunlight cause the sea water to become 

 more alkaline. Similar observations had been 

 previously made by others' upon fresh-water 

 plants in solutions containing bicarbonates. 



It seemed to the writers that this procedure 

 might be utilized in the study of photosyn- 

 thesis. After investigating a number of ma- 

 rine plants it was foimd that Ulva (sea let- 

 tuce) is very satisfactory for such experiments. 

 A piece of Ulva was placed in a beaker and 

 covered with sea water to which a little 

 phenclphthalein* had been added. It was then 

 placed in direct sunlight. In the course of an 

 houj the solution turned pink. The pink color 

 grew steadily more pronounced and at the end 

 of another hour was intense. 



It seemed evident that by measuring the 

 alkalinity which produced the change of color 

 we might arrive at a simple and satisfactory 

 method of studying photosynthesis. 



In order to measure the degree of alkalinity 

 produced by Ulva, a piece of the frond was 

 placed in a tube of Pyrex glass' (about 12 mm. 

 in diameter) in such a manner that it com- 



1 Preliminary communication. 



2 Loeb, J., "Dynamics of Living Matter," 1906, 

 p. 98. 



3 Cf. Caapek, F., "Biochemie der Pflanzea," 

 1913, 1: 519. 



•* Ten drops of saturated alcoholic pheuolphtha- 

 lein was added to 1 Uter of sea water. For class 

 demonstration more may be added. 



5 This glass was chosen because it does not give 

 off measurable quantities of alkali during the 

 period of the experiment. 



