822 



SCIENCE. 



[N. S. Vol. III. No. 74, 



horses the hairs, which up to the time of flow- 

 ering are soft and flexible, but afterwards be- 

 come stifle and needle-lilie, gather into balls, 

 sometimes becoming large enough, as in the 

 present instance, to clog the intestine and 

 cause death through peritonitis or some related 

 ailment. 



Erwin F. Smith exhibited a photograph made 

 from a poured gelatine plate, showing the bac- 

 tericidal effect of direct sunlight. He stated 

 that many parasitic bacteria are killed by light 

 and I'emarked on the hygienic importance of 

 flooding sick rooms and all living rooms with 

 sunshine. This experiment was made with 

 Bacillus tracheiphilus, the exposure being only 

 three hours. The part of the gelatine plate 

 which was covered from the light developed 

 from 6,000 to 12,000 small colonies in each 

 field of the microscope, so that the gelatine be- 

 came grayish white. The part of the plate 

 which was exposed to the direct rays of the 

 sun, a middle star-shaped portion, was easily 

 distinguishable from the rest of the plate on 

 the second day, and appeared throughout the 

 experiment (8 days) to be entirely free from 

 colonies, but a careful microscopic examination 

 at several different times showed that about 

 one bacillus in a thousand had escaped. These 

 are supposed to have been partially or wholly 

 protected from the direct action of the light by 

 germs lying above them. With longer expo- 

 sures or thinner sowings all would undoubtedly 

 have been destroj'ed. 



D. LeRoy Topping stated that Mr. Pollard 

 and himself had found Bcmiinculus ficaria, at 

 the original locality on Rock Creek, below 

 Pierce's Mill, where it had first been noticed 

 twelve years before. 



A. F. Woods showed a tomato plant which 

 had been exposed to hydro-cyanic acid. The 

 stems, petioles and midribs of the leaves were 

 killed by the gas, but the softer tissues were 

 not injured and were able to obtain all the 

 water they required through the dead dissue. 



L. H Dewey spoke of the tumbling mustard. 

 Sisymbrium altissimum, stating that it had been 

 introduced into North America from Europe 

 during the past 20 years, and during the past 

 15 years it has developed into a very trouble- 

 some weed in Assiniboia and Manitoba, N. W. 



Canada. It combines the productiveness and 

 hardiness of the mustard with the distributing 

 habit of the tumbleweed and threatens to be- 

 come a most dangerous weed in the northern 

 plains where tumbleweed and mustard thrive 

 at their best. Prof. James Fletcher, of Ottawa, 

 Canada, carefully estimated the number of seeds 

 borne by a single well developed tumbling mus- 

 tard at 1,500,000. This plant has been reported 

 from nine localities in Minnesota, Iowa, Mis- 

 souri and South Dakota, and from ballast 

 ground at Philadelphia, and freight yards at 

 Weehawken, New Jersey. 



T. W. Stanton presented a communication on 

 the Genus Semondia Oabb, stating that this 

 molluscan genus from the Lower Cretaceous of 

 Arivechi, Sonora, Mexico, which has hitherto 

 been placed in the Trigonidse, belongs to the 

 Crassaiellidse and includes the later described 

 genus Stearnsia White, from the Cretaceous of 

 Texas. 



B. T. Galloway read a paper on Recent Ad- 

 vances in our Knowledge of the Plant Cell briefly 

 reviewing the early discoveries and giving in 

 some detail the most recent contributions to th& 

 subject. A paper by C. L. Pollard on the Pur- 

 ple-Flowered Stemless Violets of the Atlantic Coast 

 was read, in the absence of Mr. Pollard, by 

 David White. Seven species were enumerated 

 in addition to the Linnsean V. pedata, the author 

 stating that botanists have differed remarkably 

 in their conceptions of specific relationships in 

 this genus ; yet while there is much individual 

 variation, the species do not intergrade to the 

 extent usually supposed. The Viola dentata of 

 Birch, V. sepiemloba of Le Conte, and V. ovata 

 of Nuttall, were restored to specific rank. 

 F. A. Lucas, 

 Secretary. 



GEOLOGICAL SOCIETY OF WASHINGTON. 



At the 49th meeting, held on May 13th,. 

 papers were presented as follows : 



The Faunal Relations of the Eocene and- 

 Upper Cretaceous on the Pacific Coast: By 

 T. W. Stanton. The Chico-Tejon series has 

 been described as a continuous series, show- 

 ing a gradual transition both faunally and 

 stratigraphically from the Cretaceous into the- 

 Eocene, the close faunal connection being 



