Septembeu 7, l!^S.1.1 



SCTEXCE. 



801 



with his masterly discussions of tlu'sc facts, 

 wliic'h are found on every page, and the vahu- 

 of which, to embrvologists, cannot l)e estimated. 

 Jloreover, to his authorship is hirgely due tiie 

 rapidly spreadiug interest in embryology in 

 England and America, — a branch of science, 

 it will be remeinbei-ed, which had previously 

 been mostly in German hands. 



One freciuently heard from him his own very 

 modest opinion of his work ; this was not at 

 all inconsistent with striking indei)endence 

 and originality of thought, and adherence to his 

 convictions. His modesty added more to the 

 recognition of his genius than any assertions of 

 his own could have done. Many were press- 

 ing forward to assert his claims, and honors 

 were fast sliowered ni)on him in England and 

 abroad. He was admired and beloved by all 

 who knew him. In scientific discussion he 

 had the rare quality, which Richard Cobdcn 

 is said to have possessed, of remaining on 

 the pleasantest personal terms with his op[)o- 

 nents. 



His energy- in all matters was great, and his 

 power of writing was unusually rapid ; but, ad- 

 vised by kind friends, he rareh- overtaxed his 

 strength, which was limited. He spent most 

 of his evenings with his friends, throwing off 

 from his mind the labors of the day, and talk- 

 ing vivaciously upon the topics of the times. 

 Wlien the first volume of Comparative embry- 

 ology was being written, he generally worked 

 but five hours daily, giving much time to 

 physical exercise, bicycling, or tennjs. into 

 which he entered with all the enthusiasm of 

 his nature. He was courageous, but not reek- 

 less ; and nothing in his previous life would 

 lead ns to suppose that the mountain cliuil) 

 which proved fatal was undertaken in a fool- 

 hard}' spirit. 



Balfour in a few years accomplished tlie work 

 of a lifetime. His influence was anil is two- 

 fold, — first, upon those with wliom he came 

 in personal contact, esi)ecially his scientific as- 

 sociates and students (an influence wliieli can- 

 not fail to endure, well expressed by Professor 

 Kitchen Parker: " I feel that his presence is 

 still with me ; I cannot lose the sense of his 



presence"); and, secon<lly, the influence of 

 his scientific work, which for genius, breadth, 

 and truth, can never be surpassed. May the 

 splendid memorial wliicii has been raiseil for 

 liim perpetuate his nol)le example as a teacher 

 and man of science ! Hknuy V. OsunuN. 



THE INTELfJGENCE OF BIUDS. 



H.vvix<; met with many instances wherein 

 birds have shown considerable ingenuity in 

 overcoming the ill results of accidents to their 

 nests, sncli as often arise during violent storms, 

 it occurred to me. at the outset of the liird- 

 nesting season of the present year, to eu'leavor 

 to test their intellectual powers generally, by 

 a series of simple experiments, lioping there- 

 in" to be able to determine to what extent 

 birds exercise their reasoning faculties. 



My experiments, and tlic inferences I drew, 

 are as follows : — 



Noting the material being gathered for the 

 nest, partially constructed, of a ehippiug-spar- 

 row (Spizella socialis), I placed a small quan- 

 tity of the same in a conspicuous position near 

 the nest. It was seen by the sparrows, and 

 examined, but none was removed. I placed 

 a portion of it upon the margin of the unfin- 

 ished nest : it was promptly removed by the 

 male bird, who used only such materials as 

 were brought to him by his mate. The follow- 

 ing day the task of lining the nest with hair was 

 commenceil. I placed a quantity of tiiis mate- 

 rial on a branch near by, but it was passed 

 unnoticed. I next placed a few hairs on the 

 margin of the nest : they were promptly re- 

 moved. On replacing many of these in the 

 nest, the entire lining was thrown out. I re- 

 placed it, and the nest was abandoned. 



A week later, finding another nest with 

 tlu-ee eggs, I adiled a few white cat-hairs to 

 tiie lining : these were removed. Others of 

 dark colors were added: they, also, were re- 

 moved. I replaced both ilark and white hairs: 

 the eggs were broken, and the nest abandoned. 



Four eggs found in a third nest were re- 

 moved without touching the nest, a wooden 

 si)Oon whittled for the purpose being used. In 

 tlu-ee days the female connni'ueed laying again : 

 four days later three eggs had been' laid, lle- 

 [ilaced the fom- I hail removed : they were 

 [iromptly thrown from the nest. I then re- 

 moved the nest, and, substituting another, 

 carefully rei)lace<l the eggs without hamlling 

 them. After what appeared to be a serious 

 consultation, the new nest was accepted. 



