Biological differences between sea waters: experiments in 1953

Abstract
The experiments during the 1953 season were arranged to investigate certain criticisms and suggestions made to us after publication of the earlier work (Wilson, 1951; Wilson & Armstrong, 1952), and there were included tests of our own devising intended to narrow the field within which must be made any search for an explanation of the observed biological differences between sea waters from different localities. We were again unable to obtain water from the Celtic Sea and once more, by kind co-operation of the Millport Marine Station, used water from the Firth of Clyde instead. Both the E1 and Clyde waters were collected on the same day and the fertilizations of Echinus esculentus were made and the experiments started 4 days later, which was the minimum time possible after collection of the Clyde water. Every experiment included a control comparison of the two waters.