Abstract
Lemna major grows and reproduces indefinitely in purified inorganic salt solution without addition of organic matter, in daylight and under electric light. Optimum p H for solution used was 4.7-4.8; indications are that this optimum varies with composition of the solution. Frequent changes of solution, which lessen bacterial growth, increase the rate of reproduction of plants. Good growth was obtained by boiling the solution andreducing contamination with bacteria by changing the plants frequently.