352 ANNUAL RECOED OF SCIENCE AND INDUSTRY. 



to do with the influence of light, but is dependent on currents 

 in the water caused by differences of temperature in different 

 parts of the fluid. He was able to produce similar figures 

 by making an emulsion of oil, colored red with henna, with a 

 mixture of alcohol and water. Sachs divides the fisrures 

 formed into two classes, the polarized and the concentric. 

 The former are formed w^hen the opposite sides of the vessel 

 containing the emulsion are unequally heated ; the latter 

 when the temperature is uniform. The fact that microzo- 

 ospores appear to collect on the side of the vessel containing 

 them which is toward the light, and the macrozoospores 

 toward the dark side, is accounted for by Sachs by the fact 

 that the macrozoospores, being heavier than the microzo- 

 ospores, sink to the bottom, and consequently, inasmuch as 

 the current on the surface of a fluid and that on the bottom 

 are in opposite directions, they would be carried in the op- 

 posite direction from the microzoosporCfS, which are near the 

 surface. 



AN IXTOXICATITnG GRASS. 



"Besides the 'Dronk' grass, i. e., Drunk Grass, of the 

 Dutch colonists in South Africa, it now appears that there is 

 in Mongolia another plant w^ith a corresponding native name 

 and similar properties. It proves to be a new species of 

 StijKi, brought from the Alachan Mountains by a Roman 

 Catholic missionary, whose horses were disabled by its inebri- 

 ating properties. The wandering Mongols of the region are 

 familiar with this grass, and use vinegar as an antidote." 

 American Journal of Science. 



SELF-BURYING SEEDS. 



The essential points of structure common to all self-burying 

 seeds are : (l) A sharp point more or less covered with re- 

 flexed hairs; (2) a strong -woody awn, bent sharply at one 

 point, so as to be divided into a lower vertical and an upper 

 more or less horizontal part, the vertical part being strongly 

 twisted on its own axis (or forming a helix, as in the Gerani- 

 acece). The hygroscopic phenomena exhibited by all the seeds 

 are: (1) On being wetted the vertical part of the awn untwists, 

 and causes the straight horizontal part to revolve and de- 

 scribe a circle in a horizontal plane ; the angle between the 



