294 THE BLOOD. 



In preparing hsemin 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 pre- 

 caution 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 hsemin crystals of varying forms will 

 be seen. 



In regard to the preparation and properties of the iodine-, bromine-, 

 and acetone-hsemin we refer to the work of STRZYZOWSKI, MERUNO 

 wicz and ZALESKi. 1 



By the action of acids upon hsemochromogen, hsematin, or haemin, a 

 new iron-free pigment, which was first closely studied by HOPPE-SEYLER 

 and called hcematoporphyrin, is produced. According to the method of 

 preparation, hsematoporphyrins having different solubilities, and whose 

 relation to each other is not perfectly clear, are produced, but all show 

 the same characteristic absorption-spectrum. The best-studied hsema- 

 toporphyrin is the one obtained according to NENCKI and SIEBER'S 

 method, by the action of glacial acetic acid saturated with hydrobromic 

 acid upon hsemin crystals, best at the temperature of the body (NENCKI 

 and ZALESKI). Another porphyrin is the mesoporphyrin obtained by 

 NENCKI and ZALESKI 2 by the reduction of hsemin in glacial acetic acid 

 by hydriodic acid and iodophosphonium. 



Haematoporphyrin, Cs^ssN^e, which, according to recent molec- 

 ular weight determinations must perhaps be doubled (PILOTY) occurs 

 according to MAC MUNN 3 as a physiological pigment in certain animals. 

 A porphyrin occurs, as shown by GARROD and SAILLET, as a normal con- 

 stituent in human urine, although only as traces and it has also been 

 observed several times in large amounts in the urine after the use of 

 sulphonal (see Chapter XIV). This urine porphyrin is generally con- 

 sidered as hsematoporphyrin. 



In the production of hsBmatoporphyrin from haemin or hsematin the iron is 

 split off. Opinions are not unanimous in regard to this process. According 



1 Strzyzowski, Therap. Monatsh., 1901 and 1902; Merunowicz and Zaleski, Bull, 

 de 1'Acad. d. Scienc. de Cracovie, 1907. 



2 Hoppe-Seyler, Med.-chem. Untersuch., 528; Nencki and Sieber, Monatshefte f. 

 Chem., 9, and Arch. f. exp. Path. u. Pharm., 18, 20, and 24; Nencki and Zaleski, 

 Zeitschr. f. physiol. Chem., 30. 



3 Piloty, Annal. d. Chem. u. Pharm., 388; MacMunn, Journ. of Physiol., 7. 



