118 KEMATEIN AND OTHER ORGANIC STAINS. 



c.c. of distilled water, filter if necessary, add 1 c.c. of 

 caustic ammonia (of O875 sp. gr.), and bring the purple liquid 

 into a capsule of sucli dimensions that its bottom be not covered 

 to a depth of more than half a centimetre. Let the liquid 

 evaporate at the ordinary temperature and protected from 

 dust. The dry product will be haematein-ammonia, about 

 equal in weight to the haematoxylin taken in the first in- 

 stance. The evaporation should not be hastened by heat, as 

 this may give rise to the formation of substances that are 

 insoluble in alcohol. The preparation should not be touched, 

 until it is dry, with any other instruments than such as are 

 made of glass, porcelain, or platinum. 



B. Alumina Hsemate'in Stains. 



180. HAYEK'S Haemalum (Haematein-alum Solution, Hsema- 

 laun; MAYER, Mitth. a. d. Zool. Stat. zu Neapel, 10, 1, 1891, 

 p. 172; see also Zeit. f. wiss. Mik., viii, 3, 1891, p. 338, a 

 very exact report, but somewhat short considering the im- 

 portance of Mayer's paper). One grm. of the colouring matter 

 (either haematein or the ammonia salt) dissolved with heat 

 in 50 c.c. of 90 per cent, alcohol, and added to a solution of 

 50 gr. of alum in a litre of distilled water. Allow the mix- 

 ture to cool and settle, filter if necessary, and add a crystal 

 of thymol to preserve from mould. 



A dark liquid of about the tint of Grenacher's borax-car- 

 mine. It 'answers to Bohmer's haematoxylin,* stains at least 

 as well, either at first, for it is ripe from the beginning, or later. 

 It may be used either in the concentrated form or diluted. 

 Concentrated, it stains almost instantaneously (sections have 

 been stained by merely pouring the liquid over them). 

 Diluted twentyfold with distilled water it will still stain 

 through the tentacles of a Tubularia in an hour. (Spring 

 water or tap water containing lime must not be used for 

 diluting ; perhaps weak solution of alum in distilled water is 

 the best means of all.) After staining, sections may be 

 washed out either with distilled or common water. The 

 solution is admirable for staining in bulk. Large objects will, 



* As with Bohmer's formula, it is not necesssaiy to conform exactly to 

 the proportions given, and a rough and ready hsBmaluin solution may be at 

 any time extemporised by adding a few drops of alcoholic solution of 

 hsematein to an alum solution of any desired strength. 



