ZOOLOGY AND BOTANY, MI0ROS0OPY, ETC. 1081 



Micro-chemical reactions of Lichens.* — Dr. E. Bachmann has 

 made some preliminary micro-chemical experiments on lichens for the 

 purpose of obtaining from the pigmented parts reactions which may 

 be applied as tests for determining the position of these cryptogams. 



The black apothecia of many crustaceous lichens he finds is due, 

 not to one black pigment, but rather to four different pigments, one 

 brown and three blue or green-blue. These are distinguished by 

 certain characteristics which are epitomized thus : — 



A. If the addition of potash solution causes little or no change in 

 the pigment, but (a) when nitric acid is added to excess a copper-red 

 coloration, confined to the surface, results, this shows the presence of 

 Blue i. (b) If, however, on the addition of the nitric acid a violet hue 

 penetrating as far as the colourless hymenium results, then Blue ii. 

 is indicated. 



B. If the addition of the potash solution is followed by the appear- 

 ance of a deep violet colour, then Blue iii. is present. 



The author's method consists merely in treating sections of the 

 apothecium with a potash solution or some other strong base, then 

 over-saturating with nitric acid, and lastly, allowing a solution of 

 calcium chloride to flow under the cover-glass (strength 'of solution 

 not given). The reaction is also obtainable from crushed prepara- 

 tions, provided that the sub-hymenial tissue is not pigmented. 



Demonstrating- Glycogen in the Basidiomycetes. f — Dr. L. 

 Errera states that not only can the presence or absence of glycogen 

 in Basidiomycetes be determined, but that by iodine staining the 

 approximate quantity is also ascertainable. 



The solution used is composed of H 2 0, 45 grm. ; iodide of 

 potassium, 0*3 grm.; iodine, 0*1 grm. After placing a section in a 

 large drop of this solution the cover-glass is imposed, a little water 

 added, and. then the slide heated until it feels rather hot to the hand. 

 If glycogen be present in extremely small quantity, the coloration 

 is rather orange than brown, and a somewhat more concentrated iodine 

 solution may be used. 



Demonstrating the Nucleus in Yeast Cells. :£ — Dr. A. Zalewski 

 demonstrates the nucleus by keeping the cells in water for some hours, 

 and then treating with hematoxylin and alum solution. In ripe 

 spores the nucleus is also easily shown. In budding and spore-form- 

 ing cells the nucleus is not discoverable. 



Imbedding Fish Eggs.§ — Mr. J. A. Eyder's method of imbedding 

 fish eggs which have been coloured in toto with borax carmine, or 

 borax picrocarmine, is as follows : — 



a. After dehydration with about forty times their own volume of 



* Zeitschr. f. Wiss. Mikr., iii. (1S86) pp. 216-9. 



t Mem. Acad. R. Sci. Belg., xxxvii. (18S5) 50 pp. 



% Verh. u. Ber. d. Krakauer Akad. d. Wiss., xiii. (1885). Cf. Bot. Centralbl., 

 xxv. (1886) p. 2. 



§ Ryder, J. A., ' On the preservation of Embryonic Materials, &c.,' 1884, 

 p. 15. Cf. "Whitman's ' Methods of Research in Microscopical Anatomy and 

 Embryology,' 1885, pp. 101-2. 



