10th October, 1965
Dear Henry,
Thank you for your letter of September 27th. Things are not going quite as quickly as I had expected but I shall definitely, shortly, be sending you a large Lungfish, as promised. We had one under observation but it had received a deep wound from the hook, when caught and I decided to use it for taking blood smears. During last week my fish assistant has been laid up and since Friday it has been a "fiesta", celebrating the third anniversary of "Freedom". But I hope to get a suitable fish during the coming week. I cannot guarantee that this will be the one which I eventually send, since there is a lot of money involved and I don't want to risk any more losses en route. I have been carrying out tests using the fish which I told you about in my last letter, and have subjected them to out-of-water tests for up to four days. One, about the same size as the larger one I sent you and which died, was put in a fairly comfortably sized container, between wet sacking, and recovered as soon as it was returned to water after 3 days. Two fish of about 26  inches were put in a biscuit tin measuring 9 inches by 5 inches deep, with a diagonal cardboard partition between them and with a few cuts made in the lid, and left there in damp sacking for 3 or 4 days respectively. They are now continuing to live perfectly happily!! Another Lungfish about 6 inches long was kept in damp cheese-cloth for two days and is perfectly happy still. In fact it would appear that the only thing which kills these creatures easily is exposure to cold -- and even those which were not practically moribund when they reached you all recovered from the effects of this. If one departs from the old idea of sending them with water, so that the container has to be sealed, the necessity of giving them an oxygen instead of an air supply is obviated. At the moment I feel very much inclined, after I have checked with experiments, to send your large fish to you in a metal box with air vents, enclosed in a plywood container. This in turn may be covered with fiberglass insulating matting and the whole sewn up in hessian cloth. But I shall make an actual test with a fish under these conditions, before sending you yours. I have also worked out a metal container, without any polythene tubing, in case I go back to the idea of sending fish to you packed with water and oxygen. I have also taken a set of measurements and have checked that fish around the 4 feet mark weigh about 18 to 19 pounds and measure just about the same number of inches in circumference at the thickest part. I have noted that you may be requiring more large specimens if we are successful in this case, and think that by the damp-packed method it may be possible to send you fish as large as it is possible for me to obtain.
I am scheduled to send a batch of Polypterus and Protopterus -- 2 dozen of each -- to Wayne State University, Detroit, early next month. Also, I have had an enquiry from the College of Physicians and Surgeons, Columbia Univ'y, New York, for supplying between 30 and 50 Protopterus, 2 to 3 feet long. The sale of pituitaries goes well and I now have a total of 280 of these on order, for the U.S.A. and U.K.
With best regard.
Sincerely,
Bryan Cooper