JOHANNES MULLER 5*7 



gator since Miiller's time. A better conception of the degree of this 

 extraordinary activity may be gained when one considers that Miiller, 

 from 1821 (when lie was nineteen years old) to the time of his death, 

 thirty-seven years later, produced, year in and year out, an average of 

 one scientific article of from three to five pages, and with from one 

 to three plates, every three weeks. And in none of these do we find 

 the spirit of his work dictated by the desire to show that he could get 

 some sort of a result out of this or that kind of investigation; but 

 rather by the burning desire to survey and to understand the interre- 

 lation of all life phenomena. 



It would seem that an unconquered field of knowledge left him no 

 rest, and was for him a stimulus to activity just as much as was the 

 knowledge of the existence of an unconquered people to Alexander the 

 Great. At the first opportunity his attention would be directed to 

 it, and never would the field be abandoned until its truths and its 

 principles were at last incorporated in Miiller's own system. This, 

 for Miiller, meant no simple undertaking. It included the universal 

 proof, the definite transformation, the deepening, the enriching, the 

 building up and the ordering of every detail of the work ; so that from 

 each such acquisition the greatest value to science invariably resulted. 



This capability of Miiller's is shown especially well in his work on 

 the Echinoderms. He early applied himself to the study of the struc- 

 ture and habits of a single group of this interesting branch of animals. 

 From this study he was led to consider the embryonic development, 

 and, finally, having pursued his investigations in this line into four of 

 the five orders of true Echinoderms, he culminated this great work by 

 subjecting the organization of the entire class of Echinoderms, both 

 recent and fossil, to a thorough revision. In this same thorough and 

 exhausting manner, Miiller attacked all possible points in the illimit- 

 able field of anatomical and physiological knowledge; and the insight 

 into nature, gained through his own exhaustive researches, yielded to 

 him a sureness of judgment which seldom failed him in the decisive 

 moments of his career. An accurate personal knowledge lay at the 

 bottom of his every work. 



In the period of his greatest activity, when he was working sim- 

 ultaneously upon " The Development of the Eeproductive Organs," 

 " The Development of the Glands," and also the first volume of his 

 " Handbook of Physiology," together with papers on " Osteology " and 

 " The Myology of the Myxinoid Fishes," he must have possessed the 

 ability to profitably divide his interest and to oscillate with a remark- 

 able ease between these several objects of thought and investigation. 

 The result is perhaps still more marvelous when we realize that, as a 

 rule, Miiller went over the same line of investigation three times : the 

 second time while he was writing his results, and the third time when 



