ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
807 
in which the Sponge was developing. Numerous larvae attached them- 
selves to these, which could be easily taken out of the water and 
examined. With the aid of silver nitrate they formed excellent 
permanent preparations, which may be set up between two cover-glasses 
in Canada balsam. The sponges were hardened by absolute alcohol ; for 
the larvae the best preparation was found to be chrom-osmic-acetic acid. 
Borax-carmine and haematoxylin were the staining reagents. The anilin 
colours, Lyons blue and malachite green, were the best for staining 
sections in which it was desired to differentiate the yolk. Im- 
bedding was effected with paraffin ; when the larvae had attached them- 
selves to Elodea-leaves this was quite easy, but when free they must first 
be fixed to a bit of liver by albumen, on account of their very small size 
— scarcely larger than a large Infusorian. Very high magnification is 
necessary to make out the component cells. 
Preparing Fungus-spores.* — Herr P. Hennings recommends a 
modification of Herpell’s plan j for fixing and preserving the spores of 
fungi. The discoloration of white spores which frequently takes place 
when this method is employed, can be prevented by saturating with 
alcohol. Coloured spores can be best preserved by making the paper 
absorb from below a solution of colophone in alcohol. 
Study of Saprolegniacese.J — Prof. M. Hartog recommends the 
following processes for fixing and staining this family of fungi. The 
reagent used for fixing is a saturated solution of corrosive sublimate ; the 
preparation is then washed with water and placed in absolute alcohol. 
The best staining reagent is a solution of the Naples boracic carmine, 
and the excess of colour is removed by an alcoholic solution of crystal- 
lized acetic acid. The staining succeeds best after the objects have been 
slightly acted on by a very slightly acidulated alcoholic solution of 
nigrosine, and is completed by a second more complete staining with 
nigrosine. The preparation may be mounted either in a solution of 
equal parts of sulphophenate of zinc and glycerin ; in Canada balsam, 
after placing in absolute alcohol, to which is added, drop by drop, 
phenicated xylol in the proportion of 3 parts of xylol to one of phenic 
acid ; or in essence of sandal- wood oil. 
Preparation of the Lower Algae. § — For cultures of the lower 
Algae, Chlamydococcus, Eudorina , Gonium , &c., M. P. A. Dangeard uses 
Van Tieghem’s moist chamber, consisting of a ring of glass fixed to the 
slide, and covered by a cover-glass, on the lower face of which is a drop 
of water containing the objects to be cultivated. The chambers are 
kept in a constantly moist atmosphere. The fixation may be effected by 
concentrated picric acid, 1 per cent, chromic acid, absolute alcohol, or 
1 per cent, osmic acid. For studying the vibratile cilia or flagels, 
chromo-osmic acid is best employed, which admits of an immediate 
observation, or the object may be fixed on the slide by concentrated 
osmic acid : it is then covered by a cover-glass and stained by a trace 
of methyl-green or by haematoxylin. To study the internal structure it 
* Yerhandl. Bot. Vereins Brandenburg, xxx. (1889) pp. 136-7. 
f Cf. this Journal, 1882, p. 122. 
X Bull. Soc. Bot. France, xxxvi. (1889), Actes du Congres de Bot., pp. ccviii.- 
ccix. § Notarisia, v. (1890) pp. 1001-6 (16 figs.). 
