Many primates used for research are also being raised in captivity by commercial animal supply houses in an effort to reduce the drain on wild populations. Yet another way of reducing demand on wild populations is the use of laboratory test - for example, cell cultures - rather than tests on live animals. Toxicity tests, for example, could be performed on cells grown in tissue culture. A surprising number of substitutes are already available. Actions such as these could stop the flow of animals from their natural habitat and help prevent the extinction of many primates.