ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 471 



Lining of Intercellular Passages.* — Hcrr H. Sclienck has repeated 

 the observations of Eussow f and others on the alleged layer of 

 protoplasm in the intercellular passages. He finds the layer described 

 by Eussow very generally present ; but agrees with Gardiner | that it 

 is not protoplasmic in its character, but is rather the lignified or 

 mucilaginous outermost layer of the cell-wall bounding the inter- 

 cellular space. As Eussow pointed out, this layer is especially 

 noticeable in bog- and water-plants, as Nupliar lutea, Potamogeton 

 natans, Lhnnanthemum nymjiliseoides, Hottonia, Utricularia, Myrio- 

 phyllum, &c. It is readily recognized by a potassium iodide solution 

 of iodine (0 • 2 per cent. I, 1 • 64 per cent, KI) and sulphuric acid 

 (when alcohol material is used 5-6 parts H2SO4 to 1 part H2O). If 

 to a section saturated with the iodine solution beneath a cover-glass, 

 the acid is introduced drop by drop, the wall of the parenchymatous 

 cells surrounding the air-passages begins to swell, and to take an 

 intense blue colour, while the passages are bounded by a delicate 

 lighter or darker yellow, or reddish-brown pellicles of a cuticular 

 character, as is clearly shown by treatment by Schultze's maceration- 

 process, viz. boiling in potassium chlorate and nitric acid, when the 

 lining in question is completely dissolved. 



Capacity of Bark for Swelling.! — According to Herr E. Mann, 

 the capacity for swelling of a zone of bark differs in intensity, as a 

 rule, in the three dimensions ; that in the radial direction being 

 almost always greater than in the other two. Each zone of the bark 

 appears to acquire a specific capacity for swelling. 



"Ant -plants" of the Indo-Malayan Archipelago and New 

 Guinea. || —Dr. 0. Beccari gives a summary of what is at present 

 known respecting this remarkable group of plants, in which ants 

 take up their residence in special chambers in the tissue, and plant 

 and animal seem each necessary to the life of the other. A good 

 example is furnished by Acacia cornigera, and its connection with a 

 particular species of ant, Pseudomyrma hicolor, which makes its nest 

 in the strong bifurcate spines of the stem and branches, after perfo- 

 rating them near their apex. They devour the pulpy interior of 

 the spine, and then find nutriment in the saccharine and nutritive 

 substances in the glandular structures of the young leaves. Here 

 they remain always on the alert, forming an army of defence against 

 herbivorous animals and other species of ants which would destroy the 

 leaves. If cultivated where these friendly ants cannot gain access 

 to it, the plant appears to perish. 



Another exceeding good illustration of these formigerous plants 

 is BIyrmecodia, an epiphytic genus of Eubiacefe, and others are found 

 scattered through the orders Myristicacete, Euphorbiacete, Verbenacete, 

 Melastomacese, and Palm«. 



* Ber. Deutsch. Bot. Gesell., iii. (1885) pp. 217-25 (1 pi.). 



t See this Journal, iv. (188i) p. 404. J Ibid., p. 585. 



§ Zeitsckr. f. Naturwiss., iv. (1885) pp. 348-73. See Bot. Centralbi xxv 

 (1886) p. G. 



II Malesia, ii. (1884) 128 pp. and 25 pis. See Arch. Ifal. do Biol., vi. (1885) 

 pp. 305-41. 



