84 CHOLESTERIN. OXY-HAEMOGLOBIN. [BOOK I. 



According to Jiidell, who worked under Hoppe-Seyler's direction, 

 100 parts of the dried blood corpuscles of man contained (1) 0*35 and 

 (2) 072 of lecithin ; 100 parts of the dried corpuscles of the dog 

 contain 0*59, 100 parts of the dried corpuscles of the goose 0'46 of 

 lecithin. 



Cholesterin. 



This body, which will be treated of fully under ' nervous tissue,' 

 is an invariable constituent of the red blood corpuscles and can be 

 separated from them by ether. For the method to be followed the 

 reader is referred to the Appendix. According to Jiidell 1 , 100 

 parts of the dried blood corpuscles of man contain 0'25 of cholesterin. 

 In the dried corpuscles of the goose the cholesterin attained the amount 

 of 0*48 per cent. 



It was formerly supposed that the neutral fats were contained in 

 the coloured corpuscles. Hoppe-Seyler 2 has however found that such 

 is not the case. 



OXY-HAEMOGLOBIN. 



For a long time the opinions of chemists and physiologists were 

 divided as to the nature of the colouring matter of the red blood cor- 

 puscles, and for the most part this was supposed to consist of a body 

 termed HAEMATIN, which, as we now know, is but a product of 

 decomposition of the true blood-colouring matter HAEMOGLOBIN, or 

 as we now term it when loosely combined, as it always is in the 

 blood, with a certain quantity of oxygen, Oxy -Haemoglobin. 



Crystals of a beautiful red colour had under certain circumstances 

 been observed to separate from the blood of different animals by 

 Leidig 3 , Reichert 4 , and Kolliker 5 , and had been afterwards more care- 

 fully described by Funke, Kunde, and Lehmann. 



The researches of several observers, but especially those of Hoppe- 

 Seyler, soon proved that the blood crystals are in reality crystals of 

 the true blood-colouring matter, which forms the chief part of the solid 

 constituents of the red corpuscles, and methods were soon found for 

 obtaining them in large quantities and in a very pure condition. 

 Thanks to these and to the application of varied methods of physical 

 and chemical research, we now have more definite knowledge as to the 

 part played by the blood-colouring matter in the processes of the 

 economy than we possess with regard to any other of the proximate 

 principles of its tissues and organs. 



1 Jiidell, loc. cit. 



2 Hoppe-Seyler, Handbuch d. physiologisch- u. pathologisch-chemischen Analyse. 

 Dritte Auflage (1870), p. 318, note. 



3 Leidig, Zeitschrift fur wiss. Zoologie. Bd. i. (1849) p. 116. 



4 Eeichert, Miiller's Archiv (1849), p. 197. 



5 Kolliker, Zeitschrift fur u-iss. Zoologie. Bd. i. (1849) p. 216. 



