ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 815 



on vegetable tissues, and they botli stain blue. The value of the 

 haematoxylin consists, however, in the fact that it does not stain the 

 membranes which are completely transformed into cork or wood. It 

 is therefore well adapted to reveal the unaltered cellulose elements 

 in cell-walls which are imperfectly lignified or suberized. With 

 Schultze's solution, which colours the lignified and suberized parts 

 yellow, the blue colour simultaneously developed in the cell-wall is 

 not brought out sufficiently clearly to enable the extent of the lignifi- 

 cation to be detel-mined with certainty." 



Canarine for Staining.* — L. Errera finds that canarine, a new 

 colouring matter derived from sulphocyanide of potassium, is 

 specially adapted for sections of stems, and the author adds that it 

 " exercises its staining action in the presence of caustic potash, which 

 will make it without doubt valuable for various researches in vege- 

 table anatomy." 



Cultivation of Bacteria upon the Slide. — Dr. Pierre Miquel 

 writes us as follows : — 



" The first efibrts towards cultivation upon the slide whilst on the 

 stage of the Microscope date far back, and have always attracted the 

 attention of micro-botanists, anxious to follow the germination of 

 microscopic spores, their growth, and fructification. De Bary, Woronin, 

 Brefeld, and many others have carefully studied the arrangements 

 necessary for these delicate cultivations. In France, Van Tieghem 

 and Lemonnier have popularized a very convenient method from their 

 memoir on which the following is derived.^ 



In the centre of an ordinary slide is fastened, by Canada balsam, 

 a glass ring from 4-5 mm. thick, cut from a tube used for organic 

 analysis, and the cut sides properly ground level. A thin cover-glass, 

 round, and of a sufficient diameter to just cover the ring without 

 overlapping the edge, is fixed on the ujDper side, by three very small 

 drops of a greasy oil, to complete the cell. In order that the interior 

 air may be .always saturated by moisture a few drops of water are 

 placed on the bottom of the cell. A small drop of nutritive liquid is 

 suspended at the centre of the under surface of the thin cover. In 

 this drop are sown the spores for cultivation. This plan allows us 

 to follow, with great facility and without interruption, from hour 

 to hour if required, all the details of the germination, characters of 

 the mycelium, and all the phases of the different fructifications, in 

 a word, the life-history of the plant, however long the time may 

 occupy. It ofiers all the advantages of cultivation upon the slide as 

 habitually practised without being liable to such errors as may other- 

 wise happen from contamination by foreign germs falling into the 

 nutritive fluid during the period of cultivation. 



The cultivating liquids employed by these investigators, who were 

 at tliat time specially occupied in the study of the Mucorini, were of 

 different kinds, as orange-juice, boiled and filtered, or a decoction of 



* Bull. Soc. Belg. Micr., x. (1884) p. 183. 

 t Ann. Sci. Nat., xviii. (1872), 



