286 THE BLOOD. 



consist of dark-brown or nearly brownish-black long, rhombic, or spool- 

 like crystals, isolated or grouped as crosses, rosettes, or stellar forms. 

 Cubical crystals may also occur, according to CLOETTA. They are insoluble 

 in water, dilute acids at the normal temperature, alcohol, ether, and 

 chloroform. They are slightly soluble in glacial acetic acid with heat. 

 They dissolve in acidified alcohol, as also in dilute caustic alkalies or 

 carbonates; and in the last case they form, besides alkali chlorides, soluble 

 hsematin alkali, from which the hsematin may be precipitated by an acid. 

 As shown by EPPINGER and then also by v. SiEWERT, 1 crystalline hasmin 

 can be reobtained from the haBmatin. 



On shaking with cold aniline and treating first with acetic acid and then 

 with ether, KUSTER obtained a product, dehydrochloride haemin, which was 

 poor in the elements of hydrochloric acid, and which again took up HC1 and was 

 converted into haxnin. By the action of boiling aniline, hydrogen is driven out 

 and a combination with aniline, without loss of iron, takes place. 



The principle of the preparation of haBmin crystals in large quan- 

 tities is as follows: The*washed sediment from the blood-corpuscles is 

 coagulated with alcohol or by boiling after dilution with water and the 

 careful addition of acid. The strongly pressed but not dry mass is rubbed 

 with 90-95 per cent alcohol which has been previously treated with oxalic 

 acid or -|-l-per cent concentrated sulphuric acid, and this is allowed to 

 stand several hours *at the temperature of the room. The filtrate is 

 warmed to about 70 0., treated with hydrochloric acid (for each liter of 

 filtrate add 10 cc. 25-per cent hydrochloric acid diluted with alcohol 

 MORNER), and allowed to stand in the cold. The crystals, which 

 separate in one or two days, are first washed with alcohol and then with 

 water. For particulars as to the various methods of preparation and 

 purification we refer the reader to the above-cited works of NENCKI 

 and SIEBER, CLOETTA, MORNER, ROSEXFELD, NENCKI and ZALESKI 

 (SHALFEJEFF), and especially to KUSTER. 2 



Hsematin is obtained on dissolving the haamin crystals in very dilute 

 caustic alkali and precipitating with an acid. 



In preparing ha3min crystals in small quantities proceed in the fol- 

 lowing manner: The blood is dried after the addition of a small quantity 

 of common salt, or the dried blood may be rubbed with a trace of the 

 same. The dry powder is placed on a microscope slide, moistened with 

 glacial acetic acid, and then covered with the cover-glass. Add, by means 

 of a glass rod, more glacial acetic acid by applying the drop at the edge 

 of the cover-glass until the space between the slide and the cover-glass 

 is full. Now warm over a very small flame, with the precaution that the 

 acetic acid does not boil and pass with the powder from under the cover- 

 glass. If no crystals appear after the first warming and cooling, warm 

 again, and if necessary add some more acetic acid. After cooling, if 

 the experiment has been properly performed, a number of dark-brown 

 or nearly black ha3min crystals of varying forms will be seen. 



1 Eppinger, 1. c.; v. Siewert, Arch. f. exp. Path. u. Pharm., 58. 



2 Kiister, Zeitschr. f. physiol. Chem., 40. 



