ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
251 
when the cuticle developes, were stained before imbeddinpj in parafSn ; 
the sections of other embryos were stained on the slide after attaching 
them with Mayer’s albumen fixative. Beautiful results in preparation 
were obtained by heating the eggs to 80° C. for 10 minutes in Kleinen- 
berg’s picrosulphuric acid (with 3 volumes of water), and preserving in 
70 per cent, alcohol. By this process the envelopes, which in the fresh 
egg adhere closely to the yolk, dilate and stand off from the surface of 
the egg, and except in the very youngest stages can be rapidly and 
easily removed with the dissecting needles. 
Investigation of Derostoma unipunctatum.* — Herr K. Lippitsch 
found his specimens of this worm preserved in sublimate, osmic acid, 
or osmic-acetic acid. The staining reagents used were hasmatoxylin, 
picrocarmine, and alum-carmine ; osmic acid is not a good preservative, 
as it causes deformations of the epithelium, but sublimate is, as with 
other Turbellaria, very good. After treatment with hasmatoxylin for two 
or three hours all the glands become very clear, and the same reagent is 
good for the nervous system when osmic-acetic acid has been previously 
used. Twenty-four hours’ stay in picrocarmine is useful for the study 
of the epithelium, nervous system, musculature of the pharynx, and 
connective tissue. Alum-carmine is also to be recommended. 
Preparation of Horny Teeth of Batrachian Larvae. f — Herr E. 
Gutzeit preserved his larvae in 0 * 2 per cent, chromic acid or in sublimate, 
and afterwards placed them in alcohcd ; they were stained in toto by 
haematoxylin or picrocarmine. Paraf&n was generally, and soap only 
rarely used as imbedding material. The sections were attached by oil of 
cloves and collodion, and Canada balsam was added. Wickersheim’s 
fluid or Miiller’s solution was used for macerating purposes, and pre- 
parations so made were preserved in glycerin-gelatin. 
Production of Colourless Spirit-preparations. J — Herr H. de Vries 
proposes the following process for this purpose : — By adding two parts 
by volume of strong hydrochloric acid to 100 parts of alcohol, the pro- 
duction is prevented of brown pigments in the parts of plants which 
are plunged when living into the mixture ; and the preparations thus 
obtained are much more beautiful than by the ordinary method. Even 
plants in which the brown pigment is very conspicuous, such as Orohanche, 
become white in this mixture ; the only case of failure was with Aucuha, 
older portions still retaining their brown colour, while younger portions 
became quite white. 
Observation of Nuclear Division in Plants.§ — Prof. D. H. Campbell 
recommends for this purpose the pollen-mother-cells of Allium canadense 
or of Fodophyllum peliatum, taken from a bud. They should be crushed 
or teased out into a mixture of equal parts of acetic acid and water, 
when the pollen-mother-cells are at once recognizable by their thick 
colourless walls ; if they are already in the required stage of division, 
they may be stained by acetic methyl-green or gentian-violet, made by 
adding a sufficient quantity of a saturated alcoholic solution of gentian- 
* Zeitschr. f. Wiss. Zool., xlix. (1889) pp. 148-9. f T. c., p. G5. 
X Ber. Deutsch. Bot. Gesell., vii. (1889) pp. 298-301. 
§ Bot. Gazette, xiv. (1889) p. 199. 
