Dr Laws was the first Director of the Tsavo Research Project. This was started in February 1967 to investigate the habitat destruction in the Tsavo National Park, in Kenya, and the part played by the elephants which had been increasing rapidly—the research team's estimate was 23,000 in the park with an additional 12,000 in the peripheral areas, a total of 35,000 ± 7,000. After nine months the research programme, which included sample kills of elephants, was interrupted by the National Parks. Dr Laws spent the next eight months trying to restart the work and to discuss his findings and proposals; no discussions took place and he resigned. The article here consists of part of a paper (slightly amended by Dr Laws) published in the Journal of Reproduction and Fertility, Supplement No 6, 1969, and reproduced by permission. It explains why he regards the sample cropping as essential to find out what is happening in the elephant populations, and whether they are regulating their numbers quickly enough to save the habitat. Since Dr Laws left the Tsavo in June 1968, the Research Project has been carried on under the direction of the Botanist Warden, Dr P. E. Glover, an article by whom appeared in the September ORYX, page 323; a comment on this by Dr Laws will appear in the next ORYX, May 1971.