252 TRANSACTIONS OF THE [JUNE 4, 
cal School, became distinguished for his skill as a surgeon, and 
was demonstrator of anatomy under Oliver Wendell Holmes. 
In 1846 he began the practice of medicine in Swampscott, Mass., 
and later he moved to Lynn and became the city physician. 
From his youth he had been an ardent lover of nature, and 
did all in his power to encourage a love of the study among the 
people. He founded the Lynn Natural History Society, and 
added much to its collections. He made a trip over New York 
State before the time of railroads, collecting specimens for its 
cabinet, and studying the fauna, flora, geology, etc. He was 
an ardent botanist and made probably the first list of plants of 
Essex County, Mass. He left copious notes of their habits, time 
of appearing, etc., showing that there was hardly a foot of this 
locality that was not intimately known to him. He made fine 
drawings of the plants, often in color, and kept what might be 
called a diary of plant-life. In 1844, he made a catalogue of 
the birds of Lynn and vicinity, which appeared as Bulletin 
No. 1 of the publications of the Lynn Nat. History Society. 
This led to his meeting the late Prof. 8. F. Baird, and the forma- 
tion of a lifelong friendship. Dr. Holder early met Prof. 
Agassiz, and often joined him at his home in Nahant, and for 
some years made many investigations, dredging and collecting, 
particularly with his intimate friend, Prof. William Stimpson. 
In 1859, he was offered anappointment as surgeon in the U.S. 
Engineer Department, at Tortugas, Fla., which he accepted. 
This step was taken partly at the instigation of Profs, Baird and 
Agassiz, and it gave him an opportunity to enter more fully into 
the studies of his choice. 
Arriving at Fort Jefferson, he began experimental studies, 
and collected hundreds of new and hitherto undescribed species 
in almost every branch of the animal (marine) kingdom. ‘These 
were chiefly sent to the Smithsonian Institution and to Harvard 
College, while many other colleges received specimens of his 
collecting. To study better the habits of animals and the 
growth of certain corals, he bad an aquarium built out into the 
water, and here carried on a systematic study of the growth of 
corals, watching them from day to day.. 
The ideas prevailing then concerning coral-growth were more 
