Dear Sir,

I have had previous occasion to correspond with you on subjects bearing on evolution, and there is one more little matter on which I should like your opinion.² As one of your disciples it has been my object to try the doctrine of evolution by survival of fitness at every possible point and amongst other things I have speculated on the origin of tails

For every tail I got a satisfactory reason, save for the bushy tail of such animals as the civet cat,³ some dogs, wolf &c. That variety long puzzled me until the accidental observation of a favourite white cat, who is perfectly deaf, solved the riddle to me On him I can perform experiments by reason of his deafness, without arousing his suspicion and I find that he uses his tail as a respirator to keep up his temperature. I catch him asleep before a German stove, lying at full length on his side with tail & limbs stretched out to enjoy the full heat. Then I intercept the heat by a screen & without waking he gradually coils himself up so as to cover as much surface as possible to save loss of heat. Then when I drive a current of cold air on him from a pair of bellows he twines his tail round him & buries his nose completely in the fur between it & the thigh, thereby establishing a natural respirator which must conserve his temperature to a very marked extent

Birds do the same thing when they bury their noses in their wings. I cannot find a bushy tailed animal which cannot curl itself up. If I could my theory would be spoilt

I mentioned this to my friend Prof Haughton⁴ of Dublin a few days ago when on a visit to him, and on a very cold morning we started round the Zoological Gardens to examine for the point. We found the civet cat & others coiled up & their noses covered with the fur. I do not know whether the observation is an original one or not, but it is at any rate interesting   I purpose communicating a short note on it to the Birmingham Natural History Society and previous to that I should like to know your opinion of my theory.⁵

Yours faithfully | Lawson Tait