Chap. I.] ACTION OP THE PARTS. 16 



limited, or quite deficient, unless the plant had the power of 

 obtaining this important element from captured insects. We 

 can thus understand how it is that the roots are so poorly 

 developed. These usually consist of only two or three slightly 

 divided branches from half to one inch in length, furnished 

 with absorbent hairs. It appears, therefore, that the roots 

 serve only to imbibe water; though, no doubt, they would 

 absorb nutritious matter if present in the soil ; for as we shall 

 hereafter see, they absorb a weak solution of carbonate of am- 

 monia. A plant of Drosera, with the edges of its leaves 

 curled inwards, so as to form a temporary stomach, with the 

 glands of the closely inflected tentacles pouring forth their 

 acid secretion, which dissolves animal matter, afterwards to 

 be absorbed, may be said to feed like an animal. But, differ- 

 ently from an animal, it drinks by means of its roots ; and it 

 must drink largely, so as to retain many drops of viscid fluid 

 round the glands, sometimes as many as 260, exposed during 

 the whole day to a glaring sun. 



[Since the publication of the first edition, several experi- 

 ments have been made to determine whether insectivorous 

 plants are able to profit by an animal diet. 



My experiments were published in * Linnean Society's 

 Journal,' '* and almost simultaneously the results of Keller- 

 mann and Von Raumer were given in the * Botanische Zeit- 

 ting." My experiments were begun in June 1877, when the 

 plants were collected and planted in six ordinary soup-plates. 

 Each plaie was divided by a low partition into two sets, and 

 the least flourishing half of each culture was selected to be 

 " fed," while the rest of the plants were destined to be 

 " starved." The plants were prevented from catching insects 

 for themselves by means of a covering of fine gauze, so that 

 the only animal food which they obtained was supplied in 

 very minute pieces of roast meat given to the " fed " plants 

 but withheld from the " starved " ones. After only ten days 

 the difference between the fed and starved plants was clearly 

 visible: the fed plants were of brighter green and the tenta- 

 cles of a more lively red. At the end of August the plants 



" Vol. xvH.. Francis Dnrwln FlelschftttteninR: " ' Bot. Zelt- 



on the ' Nutrition of Drosera unj?,' 1878. 8om(^ account of the 



rotundifoUa.' resnlts was given before the 



" " VeRetatlonBversuche an rhy.-med. Soc., Erlangen, July 



Drosera rotundifolia mlt und ohne 0, 1877. 



