ON June 7 at the California Institute of Technology a new laboratory was opened for experimental botany. It is under the direction of Dr. F. W. Went. Dr. R. A. Millikan a past president of the Institute, has called it a "phytotron" in the expectation that it may do for botany what the cyclotron has done for physics. The laboratory consists of six air-conditioned greenhouses and thirteen air-conditioned growth chambers, in which there can be produced various conditions of light intensity and quality, temperature and humidity, besides artificial rain, wind and fog. Nutrient solution is laid on to each chamber from a 1,000-gallon tank. There are arrangements for the routine photographing of plants in each growth chamber. Elaborate precautions are taken to exclude plant diseases and pests from the laboratory. The laboratory cost half a million dollars to build and will cost about 40,000 dollars a year to run. Its construction involved the solution of several difficult engineering problems. Of particular interest to plant physiologists is the claim that artificial illumination of 2,000 foot-candles can be secured by the use of fluorescent tubes operated at about four times the normal current density, supplemented by a few 60-watt incandescent lamps. It is stated that the life of fluorescent tubes under these conditions is still as much as 1,920 hours. Plant physiologists will await with interest the results of research from this novel laboratory.