ZOOLOGY AND BOTANY, MICEOSCOPY, ETC. 835 



part get washed out in the course of mounting, but the cell-walls take so 

 much of colour that their shape and parts can be clearly distinguished. 



New Application of Photography to Botany.* — M. F. Fayod pro- 

 poses a new api)lication of jihotography for the purpose of obtaining 

 accurate representations of leaves, &c,, in order to study the arrangement 

 of the Ta-cular bundles. The method consists in employing the leaf 

 itself as a negative. It is placed on a perfectly clean plate in an ordinary 

 photographic frame, and covered by a sensitized leaf of albuminized 

 paper, such as is usually employed for positive prints. The sensitized 

 jjajjer is pressed close against the leaf, and exposed to the sun in the 

 ordinary way, generally for from 5-20 minutes. The veins being 

 nsually more translucent than the mesophyll, the portions of the sen- 

 sitized paper situated immediately below them become black more 

 rapidly than those below the mesophyll, the green colour entirely 

 absorbing the rays of light; the leaf is reproduced in white on the black 

 groundwork of the paper ; every vein being represented by a black line 

 of intensity in proportion to its strength. 



Production and Preservation of Saccharine Crystals.f— Mr. Wright 

 Astley states that saccharine may be crystallized by two methods and two 

 difierently shaped crystals produced. In the one they are nearly always 

 cube-shaped, in the other nearly always rhomboidal. The first method 

 is performed on an ordinary slide. Take about 6 grams of the pure 

 powder and mix in a 2 oz. bottle three-fourths filled with water. Then 

 pour two or three drops of the mixture on a slide ; surmount this with a 

 cover-gl«ss, which clip lightly, and hold over a spirit-lamp until it just 

 boils. It is better to have too much than too little fluid on the slide. 

 Upon cooling crystals will have formed. A similar result is also 

 obtained by putting 6 grains of the pure powder in a 2-oz. bottle and 

 pouring boiling water over this and keeping up the temperature for 

 4 or 5 minutes. On cooling crystals will have formed. 



After a good mount has been secured by crystallizing on the slide, 

 brush off the loose powder round the edge of the cover-glass, and this, 

 w ith care, will adhere while a ring of brown cement is run round ; then 

 finish in the usual way. 



Crystals formed in the manner above mentioned may be kept in the 

 mother liquid in a cell. Or make a cell and jilace in it a drop from the 

 bottle containing the crystals ; leave it until the water has evaporated 

 from the cell (24 hours) ; then finish in the usual way. 



L ATHA M, V. A. — Practical Notes on Histology. 

 [Special methods for examination of the eye.] 



Journ. of Microscopy, 11. (1889) p. 217. 



C3) Cutting-, including: Imbedding" and Microtomes. 



Imbedding in Glycerin Soap.J — This method, says Prof. A. Poli, 

 has two great advantages, the soap is very soluble in water and is very 

 transparent. Hence for delicate botanical objects it is invaluable. 



* Malpighia, iii. (1889) pp. 120-8 (1 pi.). 



t Trans. Manchester Micr. Soc, 1888, pp. 15-7. 



X Journ. de Micr., xiii. (1889) pp. 337-40, from • Malpighia.' 



3 M 2 



