680 



SCIENCE 



[N. S. Vol. XL. No. 1036 



STAMENS AND OVULES OF OAENEGIEA GIGAITTEA 



Through the courtesy of Director Mac- 

 Dougal of the Desert Botanical Laboratory at 

 Tucson, Arizona, a lateral branch of the giant 

 cactus (Oarnegiea gigantea), measuring about 

 a meter in height and twenty centimeters in 

 diameter has been blossoming at intervals since 

 May in the botanical plant houses of the Uni- 

 versity of Nebraska. No less than five dis- 

 tinct sets of flowers have appeared in this time. 



From the first the number of stamens in- 

 terested us, and some estimates were made of 

 their number, but these varied so much that 

 at last it was determined that the only thing 

 to do was to make an accurate count of the 

 stamens. Accordingly Mr. E. E. Jeffs, a fel- 

 low in botany, was asked to determine the 

 number by enumerating every stamen, not 

 making any estimate whatever. The result 

 was astonishing, for it was found that there 

 were 3,482 stamens in the flower, probably the 

 largest number recorded for any flower. 



This quite naturally raised the question of 

 the number of ovules in the same flower, and 

 Mr. Jeffs accommodatingly counted these also, 

 with the result that he found 1,980 ovules. 

 Here again the number is unexpectedly large, 

 but the result is by no means as astonishing 

 as in regard to the stamens. These figures 

 are deemed worthy of publication. 



Charles E. Bessey 



The Univeesitt or Nebraska 



SPECIAL ASTICLES 



ACTIVATION OF THE UNFERTILIZED EGG BY ULTRA- 

 VIOLET RAYS 



The sterilizing effect of the ultraviolet rays 

 suggested the possibility that with their aid 

 unfertilized eggs could be induced to develop, 

 since the writer's previous experiments have 

 shown that any substance which acts as a cy- 

 tolytic agency can also produce artificial par- 

 thenogenesis. It was found, indeed, that the 

 unfertilized eggs of the sea urchin Arhacia, 

 as well as those of the annelid Chwtopterus, 

 can be caused to develop by a short treatment 

 with the Heraeus quartz mercury arc lamp. The 

 lamp was fed with a current of 3.4 amperes, 

 the voltage of which was 220. The alleged 



candle power of this light was 3,000. The eggs 

 were at the bottom of a glass dish covered by 

 a layer of 2 cm. of sea water. The dish was 

 open on top and it stood directly under the 

 lamp at a distance of 15 cm. In order to pre- 

 vent the temperature of the eggs from rising 

 above the normal room temperature the glass 

 vessel containing the eggs was surrounded by 

 melting ice. The eggs formed a single layer 

 on the bottom of the dish, since it seemed that 

 the eggs lying on top screened the eggs under 

 them from the efiect of the ultraviolet light. 



When unfertilized eggs of Arhacia were ex- 

 posed to the ultraviolet light for ten minutes, 

 many and sometimes all formed fertilization 

 membranes. In some of the eggs this mem- 

 brane was only the fine gelatinous film which 

 the writer called an atypical membrane; others 

 possessed a typical normal fertilization mem- 

 brane. When nothing further was done with 

 the eggs they underwent, at room temperature, 

 eytolysis without segmentation. When the 

 temperature was below room temperature 

 (about 12° C.) some of the eggs segmented into 

 two or four cells, but then perished. When 

 the eggs were put for twenty minutes into 

 hypertonic sea water, about ten minutes after 

 the treatment with ultraviolet light, they devel- 

 oped into larvae. The eggs had suffered, how- 

 ever, since few developed beyond the gastrula 

 stage. When the eggs were exposed too long 

 to the ultraviolet light (e. g., twenty minutes) 

 they formed fertilization membranes, but were 

 injured to such an extent that they could no 

 longer segment or develop. 



It was of interest that a cover glass of 0.1 

 mm. thickness prevented all effects of ultra- 

 violet light even if the eggs were exposed forty 

 or sixty minutes. Such eggs remained nor- 

 mal. A layer of from 2 to 6 cm. of sea water 

 did not prevent the effect of the ultraviolet 

 rays. Neither did the rather thick walls of 

 a quartz test tube. 



The membrane formation by ultraviolet rays 

 took place in the absence as well as in the pres- 

 ence of oxygen. When unfertilized eggs were 

 put into quartz test tubes from which all the 

 oxygen had been driven out by sending a pow- 

 erful current of hydrogen through for four 



