Fbbruaey 23, 1900.] 



SCIENCE. 



299 



able that none was, but that the striking 

 change depended upon the massing of the 

 dark granular matter from the rhachis to 

 the barbs and their appendages. The ab- 

 sence of definite data upon the chemistry 

 of animal pigments makes remarks in a 

 qualitative direction wholly undesirable. 



To conclude our microscopic study, how- 

 ever, we may affirm: (1) that microscop- 

 ically as well as macroscopically an appre- 

 ciable Aptosochromatic change took place 

 in the individual feathers of my Passerina 

 cyanea; (2) that this change far from being 

 analytical or retrograde was inclined to the 

 nature of constructive synthesis, probably 

 passive in nature ; (3) that the change was 

 definite as shown by comparison with the 

 blue areas of unchanged feathers ; (4) that 

 it depended chiefly upon the gain of dark 

 pigment in the vicinity of the prismatic 

 column, and (5) that there was an appre- 

 ciable difference in the amounts of blackish 

 pigment supplied to the barbs and barbules, 

 before and after the change. 



F. J. BiRTWELL. 



Albuqueeque, New Mexico. 



THE SOCIETY FOR PLANT 3I0BPS0L0GY 

 AND PHYSIOLOGY. 



The Society for Plant Morphology and 

 Physiology held its third meeting, with the 

 American Society of Naturalists and the 

 Affiliated Scientific Societies, at Yale Uni- 

 versity, New Haven Conn., December 27th 

 and 28th, with President J. M. Macfarlane 

 in the chair. For the ensuing year the 

 following officers were elected : President, 

 D. P. Penhallow ; Vice-Presidents, Roland 

 Thaxter and Erwin F. Smith ; Secretary, W. 

 F. Ganong. The following new members 

 were elected : Oakes Ames, J. M. Coulter, 

 Carrie M. Derick, B. M. Duggar, A. W. 

 Evans, M. A. Howe, L. E,. Jones, Henry 

 Kraemer, F. E. Lloyd, D. T. MacDougal, 

 Conway MacMillan, G. T. Moore, Adeline 

 F. Schively, Hermann von Schrenk, Julia 



W. Snow. The business transacted of 

 most general interest was the appointment 

 of a committee, consisting of W. G. Farlow, 

 D. T. MacDougal and H. von Schrenk to 

 consider ways of securing better reviews of 

 current botanical literature. It was voted 

 to communicate the views of the Society 

 upon this subject to the editors of the Bo- 

 taniscJies Centralblatt. The following papers 

 were presented. The abstracts are furnished 

 by the authors. 



Geotropic Experiments : De. G. E. Stone, 



Massachusetts Agricultural College. 



This paper dealt with the question at 

 which angle gravity acts most strongly on 

 a geotropically sensitive organism. The 

 results were obtained by the use of grass 

 nodes and in one or two instances the roots 

 of Vicia faba were used. Three methods of 

 experimenting touching upon the solution 

 of this problem were described. 



The first series give the results of dyna- 

 mometer experiments in which the power of 

 growth shown by different nodes placed at 

 different angles was illustrated. 



The second method consisted of taking 

 the average of a large number of cut plants 

 grown in moist sand and placed at different 

 angles. 



The third method showed the results of 

 experiments due to the after effect of stimu- 

 lation. 



The results of all these experiments were 

 similar and may be partly summarized as 

 follows : 



The horizontal position is the position of 

 greatest geotropic excitability. This is 

 shown by the increased amount of weight 

 nodes will lift in this position, the amount 

 of growth they display and the after effect 

 reactions. 



The relationship existing between nodes 

 at oblique angles and those in a horizontal 

 position is one which is proportional to the 

 cosines of their angles. This also holds 



