INSECTIVOROUS PLANTS. 49 



of independent observers, have up to the present time been almost 



ignored. 



More recently, however, they have been repeatedly verified : in 

 Germany, by Nilschke, in 1860 ; in this country by L. A. Millington, 

 a correspondent of the American Naturalist^ April, 1868; by Mrs. 

 Treat, of New 3 ev^Qj, American Journal of Science, November, 1871, 

 and American Naturalist, December, 1873 ; by Mr. A. W. Bennett, at 

 the meeting of the British Association for the Advancement of Science, 

 1873. 



It is noticeable that all of these observers unite in reporting one 

 erroneous conclusion, namely, that the movements do not result when 

 inorganic substances are placed upon the leaves. Darwin's experi- 

 ments show that although the effect is not so great and the substances 

 are not so long detained, yet such bodies as bits of cinder do possess 

 the power of irritation. 



Mrs. Treat also reported that, when a living fly was pinned at a 

 distance of half an inch from the leaves of the D. Jiliformis, the leaves 

 bent toward it and reached it in an hour and twenty minutes. Mr. 

 Darwin was not only unable to obtain any similar results, but, to 

 admit that this motion was any thing other than an accident, would 

 compel him to adopt some other theory than the one he now holds to 

 account for the transmission of the impulse to motion. 



Reference may here be made to a remarkable statement in a note 

 of M. Ziegler to the Paris Academy of Sciences, in 1872. He says: 

 "In studying these remarkable plants, I noticed that all the albumi- 

 noid animal substances, if held for a moment between the fingers, 

 acquired the property of making the hairs of the Drosera contract. I 

 also observed that such substances, when they had not been in contact 

 with a living animal, had no visible action on the hairs. This shows 

 that the simple contact of the fingers communicates to inert animal 

 substances a property which they did not possess before." Re- 

 peated experiments, in whicli every precaution was taken by Mr. 

 Darwin, seem effectually to negative this extraordinary belief of M. 

 Ziegler. 



This, then, is a brief review of the subject up to the recent publi- 

 cation of Mr. Darwin's book upon it. It has for some time been known, 

 to all who have followed the question, that he was engaged in re- 

 searches that would one day be published, and they have been waiting 

 for them with eager interest. With characteristic patience and cau- 

 tion, it is only after fifteen years of careful investigation that he puts 

 forth the results of the long series of observations. As one reads the 

 book, the most vivid impression made is by the wonderful amount of 

 painstaking labor that the record of the experiments shows. Like the 

 artist of Kouroo, he seems to have said to liimself : " Time is an ingre- 

 dient that enters into no perfect work ; and my work shall be perfect 

 in all respects, though I should do nothing else in my life." And, lo ! 

 voi,. VIII. 4 



