464 



SCIENCE. 



LN. S. Vol. XVII. No. 429. 



'Ploi-a Alpina' (1756). Hedenberg's an- 

 alysis of plant habitats would be a credit 

 to a modern student, and Amanu's Alpine 

 studies bring out much of value. A trace 

 of the principle of succession of plant as- 

 sociations is found in Biberg, who pictures 

 the changes on a rock surface from lichens 

 to the forest. 



Some Notes on the Bending of the Inflo- 

 rescence of Daucus Carota: Dr. Heney 

 Kkaemer, Philadelphia College of Phar- 

 macy. 



It was observed that the bending of the 

 peduncles of Daucus Carota at the close of 

 the day was in inverse proportion to the 

 age of the inflorescence, i. e., this bending 

 is most pronounced in peduncles bearing 

 buds and very young flowers, and decreases 

 with the development of the flowers, so 

 that the oldest flowers show little or no 

 bending of the peduncles. Furthermore, 

 all of these stages were observed on a single 

 plant. 



An examination of the anatomy of the 

 peduncles in different stages of the devel- 

 opment of the inflorescence showed an in- 

 crease in the development of mechanical 

 tissues associated with the fibrovascular 

 bundles, the amount of thickening and de- 

 gree of lignification of the walls of the 

 cells increasing with the age of the pe- 

 duncles and being greatest in the lower 

 portion and least in the upper part of the 

 same peduncle, and entirely wanting in 

 the peduncles of the btids. 



Another observation was that on cool 

 nights after cool days during both summer 

 and fall, when the temperature was about 

 10° to 15° C, there was a mai'ked diminu- 

 tion in the bending of the peduncles, even 

 in the flower buds, the latter being erect 

 in the majority of cases. On the other 

 hand, this bending was most pronounced 

 in the evening of a hot day when the tem- 

 perature ranged from 27° to 37° C. 



These observations, taken in connection 

 with others, tend to show that the bending 

 of the peduncles of Daucus Carota is not 

 due to low temperatures, but that it ap- 

 pears to be influenced by the conditions 

 affecting transpiration and is in the nature 

 of a wilting, this being most pronounced 

 in the young peduncles, which are deflcient 

 in mechanical tissues and in which trans- 

 piration is most active, and at the close of 

 the day during which the conditions for 

 transpiration have been most favorable. 



Studies upon the Cytohydrolytic Enzymes 

 Produced by Soft Rot Bacteria: Pro- 

 fessor L. R. Jones, University of Ver- 

 mont. 



The account was based upon studies 

 of Bacillus carotovorus, although related 

 organisms were used in comparison. The 

 enzyme was secured apart from the living 

 organism by four methods, as follows: (1) 

 By passing culture broths through porce- 

 lain filters, thus removing the organisms 

 and leaving the enzyme in solution in the 

 sterile liquid. (2) By heating broth cul- 

 tures to 55° C. or slightly above. Since 

 51° is the thermal death point of this or- 

 ganism, sterility was thus secured, whereas 

 the enzyme, although weakened at 58°, was 

 not fully inhibited until about 62° was 

 reached. (3) By adding the proper 

 amounts of either phenol, thymol or for- 

 malin. Chloroform did not sterilize. (4) 

 By precipitation with alcohol. 



Detailed studies were made with the en- 

 zyme secured by the fourth method in- 

 cluding the determination of the following 

 points: (a) The relative activity of the en- 

 2yme as secured by fractional precipitation 

 with increasing amounts of alcohol; (&) 

 the relative activity from filtered as com- 

 pared with unfiltered broths (porcelain 

 filters) ; (c) the relation of composition of 

 broth, and (d) of age of culture to enzyme 

 production; (e) minimum, optimum and 



