ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 741 



Method of Preparing Haematoxylon Staining Fluid.* — Dr. S. J. 



Hicksou states that the best method of preparing haiinatoxylon fluid 

 is to follow Mitchell's instructions, taking some further precautions. 



Take 56 grammes of the logwood extract, and thoroughly pound 

 it in a mortar. Then place it on a filter, and pour about a litre and 

 a half of ordinary tap water through it. The filtrate may be thrown 

 away, and the residue allowed to dry. In the meantime prepare a 

 solution of alum as follows : — Take 25 grammes of alum, and after 

 they have been thoroughly pounded in a mortar pour them into 

 250 cc. of distilled water. To this solution add strong potash until 

 a precipitate is formed which will not dissolve upon stirring and 

 standing. Pour the alum solution upon the haematoxylon residue, 

 and allow them to macerate together for three or four days in a warm 

 room. Then filter the hfematoxylon solution into a bottle provided 

 with a closely fitting stopper, and add to it 10 cc. of pure glycerin 

 and 100 cc. of 90 per cent, spirit. The residue need not be thrown 

 away, for it can be macerated again with alum solution for a week or 

 more, and a good strong stain obtained as before. When the solution 

 is thus made it should be well shaken, and allowed to stand for some 

 weeks before being used. This solution of hfematoxylon improves 

 considerably with age. The oldest which the author has was made 

 about twelve months ago, and is by far the best. 



The haematoxylon stain produced by this recipe possesses several 

 advantages over others. In most cases it difierentiates the tissues 

 admirably ; nuclei stain deeply, cell-protoplasm faintly ; it seems to 

 last a long time without showing signs of fading, and, as it penetrates 

 well, it is very useful for staining in bulk. 



Staining for the Study of Red Blood-corpuscles.t— In the study 

 of red blood-corpuscles in bone-marrow, Professors G. Bizzozero and 

 Torres employ as a staining reagent salt solution of varying strength 

 (in Reptilia • 55-0 • 60 per cent.) to which 1/10 per cent, methyl or 

 gentian violet is added. No other stain contrasts so sharply with 

 the ground-stain of the haemoglobin-containing stroma. In animals 

 with very large blood-corpuscles, subsequent treatment with 0*5 per 

 cent, acetic acid must be adopted to render the cell-substance 

 transparent. 



To study the process of division in the blood of Anura larvae, they 

 must be examined in the living state, and rendered motionless by 

 placing them before observation in 0*5 per cent, solution of curara. 



New Double Stain for the Nervous System. J— Dr. H. Sahli finds 

 the following an excellent method. 



The sections, which should not be in water for more than five to 

 ten minutes after they have been cut, are placed for several hours in 

 a concentrated watery solution of methylen-bluo, washed in water, 

 and transferred to a saturated watery solution of acid fuchsin for 

 about five minutes. They are then quickly washed in water and 



* Quint. Journ. Micr. Sci., xxv. (1885) p. 244. 

 + Arcli. Ital. do Biol., iv. (18S:{) pp. HO'.) -2'.). 

 X Zcitschr. f. Wiwa. Mikr., ii. (1885) pp. 1-7. 

 Scr. 2.— Vol. V. 3 C 



