I am now as anxious about the publication of the Quadrupeds as I ever was in the procuring of our Birds, indeed my present interest in Zoology is altogether bent toward the Completion of this department of Natural Science. Do please write to me often as I am always glad to hear from you, and when I am somewhat slow in answering your letters, be assured that it is altogether on a/c of the excess of Labour that I have to go through. Believe me with sincere good wishes Your friend and servant, JOHN J. AUDUBON. [Illustration: AUDUBON AFTER A PORTRAIT PAINTED BY JOHN WOODHOUSE AND VICTOR GIFFORD AUDUBON ABOUT 1841, NOW IN POSSESSION OF THE AMERICAN MUSEUM OF NATURAL HISTORY, NEW YORK. PUBLISHED BY COURTESY OF THE AMERICAN MUSEUM OF NATURAL HISTORY.] Although Audubon never went to Carlisle, young Baird, as we shall see, repeatedly visited him in New York and became a favorite with his family. A description of the new Flycatchers was published by the Baird brothers in 1843, and represented Spencer's first contribution to his favorite science; Audubon included their discovery in the Appendix to the seventh and last volume of _The Birds of America_ in 1844. Audubon's occupations in the summer of this year are clearly reflected in the following letter:[182] _Audubon to Dr. George Parkman_ NEW YORK, _June 20th 1841_ MY DEAR FRIEND.— I intended having written to you yesterday by Miss Shatuck, who was good enough to spend the day with us, but I was so deeply engaged on a drawing of Rocky Mountain Flying Squirrels, that the time of her departure came suddenly and I could merely ask of her to say to you, that your last letter and remittance had reached us in safety, and with the unexampled promptness shewn by you on the three occasions you have been troubled with the delivery of 46 parts of our work to 46 of our Boston subscribers; and for which as I have said before I am very sorry to have nought but our sincerest thanks and gratitude to you for this, so remarkable, proceeding. May God reward you and yours for all your generous actions.