12 THE AMEKICAN MONTHLY [January, 



bundles of both woody plants and herbs afford the chief channel for 

 the flow of water through the plant and principally in the xylene of the 

 bundles. 



Teeth of Ornithorhynchus. — Nature for Nov. 7, p. 11, contains 

 a note upon the teeth of this curious mammal and the early discovery 

 of them by Sir Edward Home, to which, in the same magazine for 

 Nov. 14, p. 31, Prof. Flower replies, showing that the teeth referred to 

 by Mr. Home are the adult plates or scales, and not the teeth of the 

 young Ornithorhynchus discovered by Mr. E. B. Poulton, and commu- 

 nicated to the Royal Society, Feb. 9, 1888, and described in vol. xlvi, 

 1889, pp. 126-138 of the Proceedings of the Society. 



Zoology of the Bermudas. — A very valuable contribution to bio- 

 logical literature is Angelo Heilprin's "Bermuda Islands." While 

 seeking to be a popular treatment of the physical and zoological feat- 

 ures of this very interesting group of islands, it is, at the same time, 

 both interesting and valuable as a contribution to the scientific knowl- 

 edge of the fauna of the islands. The number of species of animals 

 known to naturalists is largely increased by Mr. Heilprin and his able 

 collaborators in the publication of this volume. 



BACTERIOLOGY. 



By V. A. MOORE, 



WASHINGTON, D. C. 



A New Method of Staining Flagella and Cilia of Micro- 

 organisms.* — A method of staining bacteria has been devised by Pro- 

 fessor Loeffler, which is especially intended to demonstrate their flagella. 

 The cilia of infusoria and monads are also brought out very distinctly 

 by the use of the same method. The principle involved in staining 

 these minute structures is, according to Professor Loeffler, the subjec- 

 tion of the preparations to the action of the mordant before they are 

 placed in the staining fluid. After many trials the author hit upon the 

 following procedure, which he pronounces to be satisfactory. 



The Moi'dant. — To 10 c.c. of a 20 per cent, solution of tannin a suffi- 

 cient quantity of an aqueous solution of the sulphate of iron is added to 

 give the fluid a dark violet color. To this is added 3 to 4 c.c. of a log- 

 wood decoction (i part wood, 8 parts water). The liquid will now 

 have a blackish violet color. Care must be taken not to add an excess 

 of the logwood as it would interfere with the staining process. When 

 prepared the mordant should be kept in a well-stoppered bottle, and in 

 order to preserve it, 4 to 5 c.c. of a 5 per cent, solution of carbolic acid 

 may be added. 



The Staining Fluid. — To lOO c.c. of a saturated watery solution of 

 aniline oil is added i c.c. of a i per cent, solution of sodium hydrate to 

 give to it a slightly alkaline reaction. This alkaline analine water is 

 poured into a flask in which has been placed 4 to 5 grams of powdered 

 methylene blue, methyl violet, or fuchsin. The flask is vigorously 

 shaken and closed with a tightly-fitting rubber cork. This solution can 

 be kept for a considerable length of time. It must always be filtered 

 before using. 



* Centralblatt f. Bakteriologie u. Parasitenkunde, vi (1889), p. 209. 



