JOHN WILLIAM DRAPER. 427 



in 184G, reached its tenth edition in 1852 ; another on Physiology, 

 which appeared in 185G, arrived at its seventh edition in 1875. In 

 18G6 he published a text-book on Anatomy, Physiology, and Hygiene. 

 Some of the Introductory Lectures to his courses have been published ; 

 also an address before the New York Academy of Medicine, in 18(i3, 

 on the " Historical Influence of the Medical Profession." His books 

 and his lectures were vivified by his own fresh explorations into the 

 heart of his profession : the selective action of membranes ; endos- 

 mosis through thin fibres ; the measure of the force of endosmosis ; 

 the cause of the coagulation of the blood ; the theory of the circula- 

 tion of the blood ; explanation of the flow of sap ; respiration of fishes; 

 action of the organic muscle fibres of the lungs ; allotropism of living 

 systems ; new observations on the action of the skin ; function of 

 nerve vessels and their electrical analogies ; function of the sympa- 

 thetic nerve ; explanation of certain parts of the auditory apparatus, 

 particularly of the cochlea and the semicircular canals ; the theory of 

 vision ; the theory of muscular contraction — all these subjects were 

 touched by his laborious experiments. 



In 1844 Professor Draper published selections from his scientific 

 papers under the title of " Forces Producing the Organization of 

 Plants." Sir David Brewster, than whom no one of his day was 

 better qualified to speak for the sun, once said to Professor Draper 

 " that the solar spectrum is a world in itself, and that the study of it 

 will never be completed." We have lived to see that it not only is a 

 world in itself, but that it contains the seci'ets of all other worlds, and 

 is rapidly revealing them to the patient student. In 1875 this Acad- 

 emy awarded the Rumford Medals to Dr. Draper for his " Researches 

 in Radiant Energy." In 1878 he collected his scattered memoirs 

 on this subject, and published them in a single volume of nearly five 

 hundred pages. This publication he regarded as an autobiography of 

 his scientific life. That the reader may not be surprised that it em- 

 bodies the discoveries distilled from more than forty years of study, 

 he reminds him that days are often required to ascertain a fact that 

 may be stated in a single line. He says : " To a reader imbued with 

 the true spirit of philosophy, even the shortcomings easily detectable 

 in it are not without a charm. From the better horizon he has gained 

 he watches his author, who, like a pioneer, is doubtfully finding his 

 way, here travelling on a track that leads to nothing, then retracing 

 his footsteps ; and again, undeterred, making attempts until success 

 crown his exertions." Mr. Draper appreciated the Academy's award 

 as an acceptable return for all his disappointments and all his sue- 



