252 HEMOGLOBIN. 



rays of the solar spectrum, oxidised hseniochromogen is, in solutions of much 

 greater concentration, remarkably transparent for the ultra-violet. 



Hoppe-Seyler made the observation that perfectly pure solutions of hsematin 

 are quite unaffected by reducing agents, but that the addition of certain foreign 

 matters (e.g. albumin) renders reduction possible. I can, from my own re- 

 peated observations, emphatically confirm this fact. 



It has been stated above that diluted blood and solutions of oxyhgemoglobin 

 treated with acids exhibit a band in the red between C and D (of which the 

 centre is approximately situated at A 640), though it varies somewhat with the 

 nature of the acid which has effected the decomposition. If, however, blood 

 be treated with glacial acetic acid, and the mixture at once shaken with ether, 

 the latter subsequently separates, holding so much of an acid compound of 

 hfematin in solution as to possess a deep red colour. This ethereal solution, 

 in addition to the characteristic band of acid hasmatin, exhibits three other 

 bands whose positions and relative intensities are indicated in Plate II., 

 Spectrum 6. 



Hsematin hydro chloride (syn. hsemin). When a minute drop of 

 blood on a glass slide is mixed with a drop or two of glacial acetic 

 acid, and the mixture is boiled over a tiny name, and then allowed 

 to evaporate, the residue is found on microscopic examination to 

 contain innumerable reddish-brown prismatic crystals, which were 

 formerly constantly referred to as Teichmann's l crystals (after their 

 discoverer). Such crystals may be obtained from any old blood stain 

 on cloth, linen, wood, metal, etc. The stained tissue or the scrapings 

 of the stain are heated, as above, with glacial acetic acid. It is neces- 

 sary, however, in the case of stains which may have been subjected 

 to the action of water, to add a minute crystal of sodium chloride 

 to the glacial acetic acid before boiling. Hoppe-Seyler 2 subsequently 

 discovered methods of obtaining Teichmann's crystals in quantities, 

 which enabled him to examine their physical properties with some 

 degree of completeness and to analyse them, and he was able to show 

 that haeniin is a compound of heematin and hydrochloric acid, to which, 

 as a result of his more recent researches, he ascribed the empirical 

 formula C 34 H 35 N 4 Fe0 6 HCL Nencki and Sieber, 3 on the other hand, 

 assigned to hsemin the formula C 32 H 30 N 4 Fe0 3 HCl, corresponding to the 

 formula C 32 H 30 N 4 Fe0 3 , which they assign to hsematin. 



Method of preparing licemin in bulk. A method for preparing liaemin in 

 bulk was, as has been said, first devised by Hoppe-Seyler, and other methods 

 were described by Nencki and Sieber. These methods demand the ex- 

 penditure of much time, labour, and patience ; and none of them, as I know 

 from my own abundant personal experience, yield a product which can 

 compare in the absolute uniformity of its crystallisation and the complete 

 absence of all amorphous matter with the one described by Schalfijew, which 

 is as follows : 



One volume of defibrinated and strained blood is added to four volumes of 

 glacial acetic acid, previously heated to 80 C. As soon as the temperature has 

 fallen to 55-60, the liquid is again heated to 80 C. On cooling, crystals at 

 once separate, and can be seen floating in the liquid, presenting a charac- 



1 Ztschr.f. rat. Med., 1853, Bd. iii. S. 375, and Bd. viii. S. 141. 



2 Virchow's Archiv, 1864, Bd. xxix. S. 597-600; "Das Hamin," Med.-cliem. Unter- 

 such., Berlin, S. 379-385. 



3 Arch.f. exper. Path. u. PharmaJcoL, Leipzig, 1884, Bd. xviii. S. 401 ; 1886, Bd. xxi. 

 S. 325 ; 1888, Bd. xxiv. S. 430. 



