300 



SCIENCE. 



[Vol.. 11., No. .31. 



In teaching he combined manly Ibrce with 

 a deHcate regard for the feelings of his i)npils. 

 From the writer's personal impressions of him 

 as a lecturer, he did not aim at eloquence, but 

 to be understood in ever}- step ; rarelj'' looking 

 at his hearers, he spoke rapidlj- and with in- 

 tense earnestness, crowding a vast deal into 

 the hour. The main qualities of his character 

 shone forth in his lectures, — energj', which he 

 infused into his hearers ; truthfulness, which 

 soon gave implicit confidence in his state- 

 ments ; modest}' and symjjathy, which inspired 

 effort and free exchange of thought. 



Balfour's love of truth came constantly into 

 plav in his laboratorj- instruction. While 

 looking over a student's shoulder, he would 

 sometimes saj- with a laugh, "You must in- 

 terpi'ct that specimen with the eye of faith ; " 

 but this was very far from being a seiious in- 

 junction, for he exacted of his students the 

 gi-eatest caution in the progress of their mi- 

 croscopic work. However tempting a certain 

 interpretation of a specimen might be, Balfour 

 never accepted it until it rested on the clear- 

 est evidence. An instance of this sort is re- 

 called by the writer, which related to the much 

 disputed origin of a well-known embryonic 

 structure. A number of sections had been 

 prepared, scheming to confirm the view which 

 Balfour himself had advocated some time be- 

 fore ; it required considerable self-control not 

 to attach a somewhat forced meaning to 

 them : this was, however, forbidden ; and it 

 was not until several days afterwards that 

 fresh sections established the fact beyond 

 question. 



To Foster, Balfour repaid his student-debt 

 by extending, in turn, continued encourage- 

 jnent to others. He did not fear, as many 

 great teachers have, that joint labor with his 

 juniors would derogate from his reputation: 

 liis joint articles are numerous ; he was zeal- 

 ous to recognize research done b}' his pupils, 

 seeming to be prouder of this than of his own 

 work. Nothing could be more stimulating to 

 the young men about him, still distrustful of 

 their powers, than this generous co-operation. 

 Is it surprising, then, that the voluntary attend- 



ance upon his lectures increased in seven vears 

 from ten to ninctj', and that at the time of his 

 death twent}- students were engaged in difficult 

 research in his laboratory? Only those who 

 are familiar bj' experience with the few incen- 

 tives among j-ounger students to the study of 

 biology can appreciate what these numbers 

 mean. 



We need not attempt to give a full list of 

 Balfour's writings. Thej' began in 1873, his 

 twenty-first year, with a few short papers ap- 

 pearing over Foster's name and his own in the 

 Quarterly journal of microscopical science : tliey 

 terminated nine years later, with his fine work 

 upon Peripatus, published posthumously in 

 the same journal, and of which a full abstract 

 will be found farther on. His extensive in- 

 termediate works, the Elasmobranch fishes 

 and Comparative embryology, are universallj^ 

 known. 



From the first he devoted himself to embry- 

 ologj'. While this, as among the youngest of 

 the biological sciences, admits of rapid work, 

 it is far from admitting rapid generalization. 

 No other branch of morpliology requires more 

 painstaking ; the very materials one has to 

 study are minute and indefinite ; and two minds 

 will often place different constructions upon 

 the same specimen.' There is abundant oppor- 

 tunity for scientific guesswork, with the feeling 

 of security that disproval will be difficult. 

 Balfour understood the real value of guessing 

 at truth, but he alwaj-s made it ^-ery clear to 

 the reader when he was so doing ; his hy- 

 potheses were accompanied b}- definite state- 

 ments, in which the reasons pro and con were 

 set forth in all impartiality to each. Herein 

 lies a chief charm and merit of his work, its 

 brilliant suggestiveness, side by side but 

 never in confusion with well-established facts. 

 Ever}^ chapter contains half a dozen invita- 

 tions to other investigators to prove or dis- 

 prove certain provisional statements. Vast 

 as is the information contained in his Com- 

 parative embrj'ology, Balfour himself appreci- 

 ated, that, as far as mere facts went, the first 

 volume would be somewhat out of date before 

 the second was in press. Not so, however, 



