SCIENTIFIC SOCIETIES. 67 



Mr. Thomas Christy exhibited and made observations upon some 

 remarkably long tendrils of Landolphia Kirkii, which served as an 

 illustration to a paper subsequently read by Mr. Henslow. 



Mr. J. E. Harting exhibited and made some remarks upon the plant- 

 debris ejected in the form of "pellets" or "castings" by Rooks, and stated 

 that a number of these pellets which had been examined were composed of 

 the cuticles of the succulent roots of the couch-grass, Triticum repens, 

 commonly called " scutch," "squitch," and " twitch" -grass, a most trouble- 

 some weed to the farmer. Mr. Harting also exhibited a rare Australian 

 duck, Stictonetta navosa, Gould, which had been obtained at Gippsland 

 Lake, Victoria, and of which very few examples were to be found in 

 collections. 



A paper was then read by the Rev. G. Henslow, M.A., on the origin of 

 the structural peculiarities of climbing stems by self-adaptation in response 

 to external mechanical forces. The purport of this paper was to prove by 

 an appeal to facts and experiments the existence of the power in living 

 protoplasms of responding to external and purely mechanical forces by 

 enveloping supportive tissues, by means of which the plant is enabled to 

 resist the effects of gravity, tensions, pressures, &c. In the case of 

 climbers, not only is this principle illustrated wherever a force is felt; but 

 whenever a stem is relieved of a force atrophy or arrest of mechanical 

 tissues takes place, supplemented, however, by an increase in the number 

 and size of vessels. The conclusion arrived at was that while, on the one 

 hand, the peculiar structures of climbers are all the outcome of a response 

 to the external mechanical forces acting directly upon the stems, such 

 structures are precisely those which are most admirably suited to the 

 requirements of the stems themselves. The variations of structure charac- 

 teristic of species, genera, and orders of climbing plants have been thus 

 acquired in a definite direction, viz. of direct adaptability, this being effected, 

 according to Mr. Darwin's statement, " without the aid of natural selection." 

 The paper was criticised by Dr. D. H. Scott, Prof. Reynolds Green, and 

 Mr. G. Murray, who, while testifying to the number of interesting facts 

 brought forward by Mr. Henslow to support his views, were yet unable to 

 agree with him in some of his conclusions. The paper was illustrated 

 by a great variety of specimens and drawings, and was listened to with 

 considerable interest by a very full meeting. 



Zoological Society of London. 



January 16^, 1894.— Sir W. H. Flower, K.C.B., LL.D., F.R.S*, 

 President, in the chair. 



The Secretary read a report on the additions that had been made to the 

 Society's Menagerie during the month of December, 1894. 



