Febbuaky 5, 1909] 



SCIENCE 



233 



peared to confinn the observer in the view that 

 bog-water does contain toxic substances. 



Geo. F. Freeman tells (Bot. Gaz., Aug., 

 1908) of " A Method for the Quantitive De- 

 termination of Transpiration in Plants," 

 which consists in using phosphorus-pentoxid 

 TJ-tubes through which a current of air is 

 drawn by an aspirator. This air current 

 previously flows over the enclosed foliage of 

 the plant under examination, and the moisture 

 which it contains (as a consequence of trans- 

 piration) is absorbed by the phosphorus- 

 pentoxid. The increase in weight of the latter 

 enables the experimenter to determine the 

 amount of transpiration. 



Somewhat like the preceding is Dr. G. J. 

 Peirce's paper on "A New Eespiration Calorim- 

 eter" (Bot. Gaz., Sept., 1908) in which after 

 pointing out some errors and crudities in some 

 popular lectures and experiments he describes 

 the simple apparatus which he has found use- 

 ful. Dewar flasks (with double walls enclos- 

 ing a vacuum) were used, and it was found 

 that these when silvered enabled the experi- 

 menter to obtain results that were quite im- 

 possible with other apparatus. Dewar flasks 

 are also popularly known as " thermal bottles," 

 but those supplied in chemical glassware are 

 more serviceable and less expensive. 



The question of the effect of illuminating 

 gas upon plants is one of much popular in- 

 terest and has been investigated by Messrs. 

 Crocker and Knight and the results published 

 in a paper (" Effect of Illuminating Gas and 

 Ethylene upon Flowering Carnations ") in the 

 Botanical Gazette for October, 1908. They 

 find that one part of gas in 40,000 parts of air 

 kills the young flower buds, and that 1 part of 

 ethylene in 1,000,000 parts of air is harmful. 



J. F. McClendon's paper " On the Xero- 

 phytic Adaptations of Leaf Structure in 

 Yuccas, Agaves and Nolinas" (Am. Nat., 

 May, 1908) brings together a number of in- 

 teresting structural details in regard to the 

 epidermis, stomata and general leaf-structure 

 of these plants. 



Here should be noticed Professor L. H. 

 Harvey's very helpful paper on the " Floral 

 Succession in the Prairie-grass Formation of 



Southeastern South Dakota " (Bot. Gaz., Aug. 

 and Oct., 1908) in which he gives a good idea 

 of the vegetation of the region by an un- 

 usually clear discussion, aided by carefully 

 selected photographs. 



A suggestive paper entitled " A Study of the 

 Variation of the Number of Ray Flowers of 

 Certain Compositae " by Mr. W. Dudgeon re- 

 cently appeared in the Proceedings of the 

 Iowa Academy of Sciences (Vol. XVI.), in 

 which the author shows by careful counts of 

 several thousand heads from different locali- 

 ties, first, that there is a wide variation in the 

 number, and second, that the highest numbers 

 are the same in the different localities. Thus 

 in Rudbechia hirta the rays range from 2 to 

 28, with the greatest number of heads having 

 13. RudbecMa trilola ranges from 5 to 14, 

 with 8 as the normal, while in Melianthus 

 grosse-serratus the range is from 1 to 25, with 

 13 as the normal. 



Dr. Henri Hus contributes a paper in the 

 February American Naturalist to the obscure 

 subject of teratology, under the title of 

 " Fasciations of Known Causation," in which 

 he enumerates four " causes " : (1) mechan- 

 ical, (2) cases where no injury can be traced, 

 (3) fungi, (4) insects. In his paper these are 

 discussed at length, and numerous examples 

 are cited. 



ECONOMIC BOTANY 



r. C. Stewart, of the New York Agricul- 

 tural Experiment Station (Geneva), prints an 

 instructive summary of the botanical investi- 

 gations made in the station during the past 

 twenty-five years. And it is an excellent 

 record, and had the station accomplished no 

 more in this time than is here enumerated in 

 one department alone, it would have fully re- 

 paid the state for the money expended. On 

 looking over the paper one is amazed at how 

 much has been done in these twenty-five years. 

 The diseases of more than thirty kinds of 

 plants have been studied, including most of 

 the standard crops of the state, as apple, 

 asparagus, bean, beet, cabbage, carnation, 

 cauliflower, celery, etc. The alphabetical ar- 

 rangement makes it easy to find what has been 

 done in the study of the diseases of this or that 



