474 PROCEEDINGS OF THE AMERICAN ACADEMY 



investigations of Natural History, his volumes on the " Herpetology of 

 the United States" being perhaps one of the first publications to attract 

 the attention of European scientific men to the progress of the natural 

 sciences in the United States. The naturalists of the present day cannot 

 be too grateful to him for having produced a work which at the time not 

 only had no equal in Europe in its special department, but will remain 

 hereafter the standard work, and the basis for all subsequent works on 

 the subject in this country ; .although at the time' of its publication 

 the difficulties which beset an author, in the way of want of libraries, 

 total absence of scientific tradition, and lack of accurately determined 

 material, can hardly be appreciated by the naturalists of the present 

 time, with their daily increasing facilities for study and comparison. 

 These difficulties only a true love of his science could have sur- 

 mounted ; and the example given by Dr. Holbrook will long be bene- 

 ficially felt throughout the country. 



After the completion of his " Herpetology " he visited Europe again, 

 and renewed the relations he had formed before with the scientific 

 men abroad, more especially with the professors of the Jardin des 

 Plantes. 



On the breaking out of the war, he was engaged upon his " Ichthy- 

 ology of South Carolina," for which the State of South Carolina had 

 given him a moderate grant to defray a part of the expenses. The 

 first edition was nearly completely destroyed by a fire in Phila- 

 delphia, and the war put an end to all further work. It is thus 

 unfortunately left incomplete. During the war he served as a phy- 

 sician in the Southezm army, and in spite of his old age was often 

 compelled to share the rations and be exposed to the hardships of the 

 common soldier. At the close of the struggle he was among the first 

 who were willing to make all reasonable concessions for the restoration 

 of peace, and who returned with unimpaired affection to his Northern 

 friends, although the result had involved him in the common ruin. 



For the last years of his life he spent the summers in New England. 

 He died on the 8th of September, 1871, at Norfolk, Massachusetts, at 

 his sister's residence, in the village where he had spent his infancy and 

 boyhood, surrounded by his family and friends. 



Dennis Hart Mahan was born April 2, 1802, in the city of New 

 York. His boyhood was passed in Norfolk, Virginia. While pursuing 

 the study of medicine with Dr. Archer, in Richmond, Virginia, he 



