360 



SCIENCE 



[N. S. Vol. XLIII. No. 1106 



as an election committee^ and will communicate 

 with all members of the association, first, to se- 

 cure a primary ballot of nominations, and again 

 to secure a ballot of election; votes being taken 

 from a list of candidates receiving the highest 

 number of ballots in the primary. In its modified 

 form this method of election is now before the 

 association as a constitutional amendment. 



A resolution was passed to the effect that the 

 association "discourage the use of mental tests 

 for practical psychological diagnosis by individ- 

 uals psychologically unqualified for this work." 

 By resolution, also, the retiring president was au- 

 thorized to appoint a committee for the purpose of 

 expressing approval of plans for the establish- 

 ment of a station for the study of the behavior 

 of primates. The committee, as appointed, con- 

 sists of Professor J. K. Angell, University of Chi- 

 cago, chairman; Professor Raymond Dodge, Wes- 

 leyan University; President G. Stanley Hall, Clark 

 University; Professor G-. M. Stratton, University 

 of California, and Professor E. L. Thorndik.?, 

 Teachers College, Columbia University. 



R. M. Ogden, 



Secretary 



THE BOTANICAL SOCIETY OF 

 AMERICA. Ill 



Fiber Measurement Studies: A Comparison of 

 Tracheid Dimensions in Longleaf Pine and 

 Douglas Fir, with Data on the Strength and 

 Length, Mean Diameter and Thickness of Wall 

 of the Tracheids: Eloise Gerrt. 

 This paper is a progress report on the fiber di- 

 mension studies that are being made as a part of 

 the investigation into the mechanical, physical and 

 chemical properties of Longleaf pine, Finns palus- 

 tris and Douglas fir, Fseudotsuga taxifolia at the 

 U. S. Department of Agriculture, Forest Products 

 Laboratory, which is maintained in cooperation 

 with the University of Wisconsin at Madison, Wis- 

 consin. The microscopic investigations were made 

 at every tenth annual ring on large cross section 

 from old trees. The following data were recorded 

 for each ring: Age, width, per cent, of summer- 

 wood, height above the ground, distance from the 

 pith, and resin content. Fifty measurements were 

 made of the length, mean diameter and thickness 

 of wall to obtain average. The spring and sum- 

 mer ^wood were recorded separately. A number of 

 tracheids proportional, respectively, to the per 

 cents, of spring and summer-wood in the ring were 

 measured. This data supplements that previously 



presented. It includes a summary of over 7,000 

 measurements on Douglas fir and 5,000 on longleaf 

 pine. The results are as follows: (1) No evidence 

 could be found for a constant fiber length such as 

 was reported by Sanio for the Scots pine. (2) 

 There are many more bordered pits in the spring 

 than in the summer-wood tracheids. The ends of 

 the tracheids may frequently be blunt or forked. 

 They are generally very pointed in the summer- 

 wood. (3) The summer-wood tracheids in any ring 

 are, in general, shorter than the spring-wood 

 tracheids in all the material studied. (4) There is 

 a rapid increase in all dimensions during the first 

 twenty years. (5) The variation in length in a 

 single tree was found in one disk to be .80-7.65 

 mm. (6) A direct relation appears to exist in the 

 Douglas fir studied between the thickness of the 

 cell walls of the summer-wood and the strength of 

 the material. The thickness of wall and strength 

 of material were both low in young material. (7) 

 No marked relation was found between width of 

 ring and fiber dimensions. A tendency was noted 

 for the young wide-ringed material to have rela- 

 tively short, narrow tracheids with thin walls. 

 (8) In studying a 455-year-old Douglas fir the 

 possibility was considered of finding indications 

 of old age or decline indicated in the size of the 

 elements. No such effect was discovered. (9) 

 The Douglas fir and pine did not vary widely in 

 the dimensions of their elements. The thickness 

 of wall averaged high in the longleaf pine, but the 

 diameters were somewhat less than those in fir. 



Xerofotic Movements in Leaves: Frank 0. Gates. 

 Xerofotic movements are paratonic movements, 

 caused by unequal drying effects in direct sun- 

 light, manifested by an upward bend in the leaf- 

 lets, or the curling upward of the blade. The up- 

 ward movement is produced by differential turgid- 

 ity in certain cells. The greater turgidity of the 

 cells on the lower, less exposed side causes the 

 organ to move upwards. In the localized xero- 

 fotic response, the differential turgidity is largely 

 confined to a small region, for example, the pul- 

 vini of leguminous leafiets. In the generalized 

 response, the blade of the leaf curls or rolls up- 

 wards. The monocot families, Poaeeae, Araceae, 

 Marantaceae and Zingiberaeeae furnish examples 

 of the generalized response. The Leguminosae 

 furnish the best examples of the localized re- 

 sponse, with which this paper deals. Whether the 

 night position of the leaflets is erect or drooping, 

 the xerofotic response is between 45° and 70° 

 above the horizontal or normal day position. 



