412 THE BLOOD, BY ALEXANDER ROLLETT. 



moglobin ; this can easily be obtained in the crystalline condi- 

 tion. Haemoglobin crystals have long been known as blood 

 crystals, and have been subjected to microscopical scrutiny. 



In the first instance they were recognised accidentally, Rei- 

 chert* having observed them in a preparation from the guinea- 

 pig preserved in alcohol, in the form of tetrahedra. Fiinke,f 

 Kunde,J Schwann, at a later period obtained the crystals me- 

 thodically from blood treated with water, and found that the 

 crystals of colouring matter from the blood of different animals 

 presented different crystalline forms, whilst those from the 

 same animal were for the most part identical. Those from dif- 

 ferent animals were at first considered to belong to very different 

 crystalline systems. 



It has been more recently ascertained that blood crystals can 

 not only be obtained by destroying the blood corpuscles with 

 water, but that an entire series of conditions which render the 

 blood carmine in colour by destruction of the corpuscles also 

 lead to the production of haemoglobin crystals. Thus, for in- 

 stance, Rollett has shown that freezing and subsequent thawing 

 of the blood, as well as the discharges of voltaic electricity ; 

 Rollett and A. Schmidt, that the alteration which the cor- 

 puscles undergo at the positive pole of a constant current ; Max 

 Schultze, that the elevation of the temperature of the blood by 

 means of a water bath at 60 C. (140 Fahr.) ; Bursy, that the 

 addition of powdered salt ; Y. Wittich, that the addition of 

 ether, or transmission of ether vapour ; Bottcher, that the ac- 

 tion of chloroform ; and Kiihne, that the alkaline salts of the 

 biliary, acids, produce the same effect. 



From each drop of such lake-coloured blood a large number 

 of beautiful crystals may be obtained on the object slide of a 

 microscope. Such crystals, obtained in constantly increasing 

 numbers from different species of animals, and examined with 

 still increasing care, are now proved to belong to two different 



* Miiller's Archiv, Jahrgang, 1849, p. 197. 



t Zeitschrift fur rationelle Medicin, N. F., Band i., p. 172 ; Band ii., 

 p. 199. 



% Idem, Band ii., p. 271. 



Handbuch der PhysioL Chemie, Band i., p. 365 ; Band ii., p. 151. 



