92 DR. LOUIS ELSBERG. 



did not enable me to arrive at a conclusion concerning its 

 intimate structure. 



Francis Darwin has discovered protoplasmic filaments pro- 

 truding from the cellulose investment of the glandular hairs 

 on the leaves of Dipsacus sylvestris (' Quarterly Journal of 

 Microscopical Science/ 187T, p. 245). Previously, Hoffman 

 (" Ueber contractile Gefilde bei Blatterschwammen," * Botan. 

 Zeitung,'1853,p. 857, and 1859, p. 2 14) had described contractile 

 filaments projecting from cell walls in Amanita (Agaricus) 

 muscaria, and although De Bary has expressed the opinion 

 that these are not protoi)lasmic, Darwin believes them to be 

 so C Quart. Journ. Mic. Sc.,' Jan., 1878, p. 74). Later, W. J. 

 Beal (' American Naturalist,' October, 1878, p. 643) described 

 threads, but does not say that they are protoplasmic, project- 

 ing from the end of hairs of several plants. Darwin has 

 observed filaments of living matter, emanating from the in- 

 terior of plant cells, pierce the cellulose frame. They pro- 

 truded from terminal cells only, and of course showed no 

 interconnection between neighbouring cells. Such intercon- 

 nection I can now demonstrate. 



My first successful observations were made in specimens of 

 the flowers of flowering flax (Norimbergia gracilis), and of 

 the leaf and stem of the common india-rubber plant (Fie us 

 elastica), and were obtained as follows. The analogy between 

 epidermal layers, as well as other parts of a plant, and animal 

 epithelia, led me to the inference that reagents successfully 

 applied for elucidating the structure of animal epithelia might 

 serve for the same purpose in plants. Now, each epithelial 

 body is a nucleated, reticulated bioplasson mass, enclosed by a 

 continuous layer of bioplasson and separated from all its 

 neighbours by a cloak of cement-substance. The cement-sub- 

 stance answers to the cellulose wall of plant cells, and as a 

 memento of Schleiden and his cell doctrine, I would advocate 

 not only the retention of the term cellulose, but its extension 

 to animal tissues, i.e. to take the place of the term cement- 

 substance. It is known to histologists that the cement-sub- 

 stance is traversed by numerous conical filaments which by 



