122 PREPARATION AND CRYSTALLOGRAPHY OF HEMOGLOBINS 



hour, the whole mass became crystalline, yet the crystals, because of their 

 smallness, were unsuited to investigation. The most beautiful crystals could 

 be obtained with ethylidene chloride according to the following method: A 

 drop of blood is thoroughly mixed with an equal amount of ethylidene 

 chloride, the cover-glass is placed on it, and the preparation set aside in a 

 cool place. After the course of 10 to 12 hours it is entirely filled with 

 crystals. With amyl nitrite or pyridine forms similar to these could not be 

 obtained. All the crystals were oxy hemoglobin. Regarding the form of 

 the oxyhemoglobin crystals of the guinea-pig, Donogany adheres, on the 

 basis of the geometric and optical characteristics, to the view of von Lang 

 that they are sphenoids belonging to the rhombic system. In a later article 

 (Zeit. f. Krystallographie, 1894, xxm, 499) Donogany publishes the results 

 of his crystallographic studies of hemoglobin crystals, which will be referred 

 to in later chapters of this memoir. 



Crystals were easily obtained from human blood by pyrogallic acid 

 and by the aid of putrefaction. Donogany first reduced the hemoglobin 

 with a 10 per cent solution of sulphide of ammonium, which, however, is 

 not necessary when using old decaying blood. After an interval of 5 to 6 

 hours crystals separate in the form of rather thick, flesh-colored or purple- 

 red needles. After 12 to 24 hours the individual crystals are pretty well 

 formed. Contrary to Wedl's assertion, Donogany observed that the crystals 

 can not be kept, since they burst in the course of 2 to 3 months in spite of 

 being properly sealed. He states that the crystals produced in decaying 

 blood are of reduced hemoglobin and that they may be changed into oxy- 

 hemoglobin without change of form. He succeeded in producing only 

 reduced hemoglobin directly from the human blood, and he believes it 

 doubtful whether by the influence of atmospheric air these crystals can be 

 changed to oxyhemoglobin. Oxyhemoglobin was prepared by means of 

 Canada balsam, xylol, damar varnish, chloroform, alcohol, amyl and methyl 

 alcohols, acetone, valerian oil, methylene chloride, and ethvlene chloride. 

 Pyrogallic acid and freezing gave only reduced hemoglobin. The crystals, 

 he states, belong to the rhombic system. Wedl had produced reduced 

 hemoglobin crystals by means of pyrogallic acid from dried blood 3 days 

 old, and Donogany modified this method for the production of hemoglobin 

 crystals from dry blood powder (1 year old). The powder was dissolved 

 in a 5 to 10 per cent solution of sulphide of ammonium, pyrogallic acid was 

 added, and crystals appeared after 10 to 12 hours. After the course of 24 

 to 48 hours crystallization had ceased. The crystals obtained from horse, 

 cat, and rabbit blood in this way were very beautiful, and large crystals 

 (1 cm. long) were not rare. The crystals were chiefly thin needles, broad 

 prisms, and rhombic plates. In human blood, besides these forms, there 

 appeared right-angled truncated prisms and forms similar to hexahedrons. 

 Experiments with bloods of other animals gave less favorable results. The 

 crystals were doubly refracting and consisted of reduced hemoglobin. 



The sulphate of ammonium process devised by Hofmeister (Zeit. f. 

 physiol. Chemie, 1890, xxiv, 165) for preparing crystals of egg albumin, 

 and subsequently used by Giirber (Wiirzburger physiol. medizin. Ges., 



