88 



ELEMENTARY COMPOSITION OF OXY-HAEMOGLOBIN. [BOOK I. 



The cakes of crystals thus obtained are mixed with water holding 

 one-fourth of its volume of alcohol in solution and again centrifugalized. 

 By repeating this process the crystals are obtained free from serum- 

 albumin. If requisite the crystals are dissolved in water and recrystallized 

 by the method mentioned under IV. 



VIII. In order to obtain very large crystals of oxy-haemoglobin for 

 microscopic examination, Gscheidlen 1 seals defibrinated dog's blood which 

 has stood in the air for 24 hours in narrow glass tubes (vaccine tubes 

 answer well), and keeps the tubes for some days at a temperature of 

 37C. On opening these tubes and emptying their contents into a 

 watch-glass, and allowing some time for evaporation to take place, there 

 are formed crystals of extraordinary size. 



Elementary The analyses of Carl Schmidt and Hoppe-Seyler 



composition have shewn that crystallized oxy-haemoglobin is a body 

 of oxy-hae- O f perfectly constant composition. Unlike any other of 

 the proximate constituents of the animal body it con- 

 tains the element iron. 



The following table exhibits the mean results of the analyses of 

 Hoppe-Seyler of oxy-haemoglobin from various animals and from the 

 horse. The former were published in 1868 2 , the latter in 1878 s ; 

 the latter are so different from the former as to be not above 

 suspicion, especially as they were not actually obtained by Professor 

 Hoppe-Seyler but by an assistant. 



PEK-CENTAGE COMPOSITION OF CRYSTALLIZED OXY-HAEMOGLOBIN 

 DRIED AT 100 C. 



From the analyses of Hoppe-Seyler (excluding that of horse's 

 blood, which is more recent) and of C. Schmidt, Preyer deduced the 

 following as the mean per-centage composition of oxy-haemoglobin : 



1 Gscheidlen, "Darstellung von Hamoglobin Krystallen zu mikroscopischer Beo- 

 bachtung." Physiologische Methodik, p. 361. 



2 Hoppe-Seyler, "Beitrage zur Kenntniss des Blutes des Menschen und der 

 Wirbelthiere." Med. Chem. Untersuchungen, Heft in. (1868) p. 370. 



3 Hoppe-Seyler, " Weitere Mittheilungen iiber die Eigenschaften des Blutfarbstoffs." 

 Zeitschriftf. phys. Chemie, Vol. n., p. 150. 



