ZOOLOGY AND BOTANY, MICKOSCOPY, ETC. 285 



The author considers the conduction of the sensitiveness to be 

 not altogether due to the continuity of the protoplasm from cell to 

 cell, since in the case of Mimosa such continuity could not be demon- 

 strated to extend to the epidermis ; the sensitiveness is, on the 

 contrary, conveyed through the cell-walls to the protoplasm. In 

 hiany cases there were found in the tendrils pits in the outer wall of 

 the epidermal cells, which appeared to play a part in the conduction 

 of the irritation. In Mimosa the author regards the movement of 

 water as the chief agent in the transmission of the irritation ; the 

 protoplasmic threads may have more to do with the sensitiveness of 

 tendrils. 



Polarization-phenomena of Tissues.* — Dr. N. J. C. Miiller de- 

 scribes the optical properties of various parts of plants which he 

 refers to a small number of types, and traces to the molecular forces 

 which were active in their formation. 



Exhalation of Ozone by Flowering Plants.f— Dr. J. M. Anders 

 has repeated his experiments on this subject, the test employed being 

 papers moistened with tincture of guaiacum (8 parts resin to 90 parts 

 alcohol). The general conclusions are that scentless plants exhale only 

 a very small amount of ozone, or none at all ; while scented plants, 

 whether flowers or leaves, are powerful generators of ozone. This is 

 especially the case with the pine and the hemlock {Ahies canadensis^ 

 As a control, to insure that the blue colour of the guaiacum-paper was 

 not due to the presence of alkaline substance, reddened litmus-paper 

 was also used. 



Disinfection of Plants. | — Sig. F. Sestini points out the incon- 

 veniences of the method of disinfecting vines attacked by Phylloxera 

 by means of hydrocyanic acid. He proposes instead the use of 

 sulphocarbonate of potassa, which he prepares in the following way. 

 One part by weight of the sulphocarbonate is dissolved in 400 parts 

 of water, and this must then be applied to the roots or other parts 

 affected so that they are under its influence for about an hour. 



Desiccation of Plants in Aqueous Soliitions.§ — M. A. Levallois 

 finds that if an orange-branch is placed in a concentrated solution of 

 calcium chloride it goes through all the phenomena of withering 

 from loss of water, leaves, stem, and flower all losing weight, the 

 total weight diminishing from 25 to 10*5 grm. Similar results were 

 obtained with leaves of the scented geranium and mint ; while flowers 

 by themselves of the rose, jasmine, orange, or tuberose lost but very 

 little in weight, their surface being protected against the action of 

 the calcium chloride. The desiccation of leaves was nearly as great 

 as that caused by a stove, and was in proportion to the desiccation of 

 the solution. After a time, however, an opposite process sets in, and 

 the leaves regain their original weight. 



* Ber. Deutsch. Bot. Gesell., iii. (1885) pp. 226-9. 



t Amer. Natural., xix. (1885) pp. 858-65. Cf. this Journal, iv. (1884) p. 777. 



X Atti Soc. Toscana Sci. Nat., iv. (1885) pp. 172-6. 



§ Comptes Reudus, cl. (1885) pp. 1175-6. 



