i 9 4 HAEMOGLOBIN. 



which is sparingly soluble in dilute alcohol, especially at low tempera- 

 tures, to crystallise. In the case of animals, the haemoglobin of whose 

 blood is very sparingly soluble, the addition of alcohol or ether is often 

 dispensed with. We shall, in the first place,' describe those methods 

 which readily furnish haemoglobin crystals for the purposes of micro- 

 scopical research, and then the methods which are employed for the 

 preparation and purification of large quantities of haemoglobin. 



Methods employed in preparing small quantities of haemoglobin 

 for microscopic examination. 1. Funkes method. 1 From the blood of 

 those animals whose blood crystallises readily, but especially in the 

 case of the rat, oxyhsemoglobin can be obtained for microscopic exami- 

 nation in three or four minutes, by receiving a drop of blood on a 

 glass slide, adding a drop of distilled water, mixing the two liquids 

 by means of a needle, and spreading the mixture over the central part 

 of the slide. When the edges of the liquid commence to dry, cover 

 with a microscopic covering glass. Crystals of haemoglobin form at 

 once. 



2. Rollett's method? A platinum capsule is placed in a freezing 

 mixture, and freshly defibrinated blood is poured into it, so as to convert 

 it into a lump of red ice. After being in the freezing mixture for half 

 an hour the blood is allowed to thaw gradually, and the contents of the 

 capsule are poured into a glass vessel of such dimensions that the 

 bottom is covered by the lake-coloured blood to a depth of 15 mm. ; 

 the glass vessel is then set aside in a cool place. In a short time, 

 the blood of rats, of guinea-pigs, and of squirrels, treated by this method, 

 furnishes well-formed crystals. 



' 3. Grscheidlens method. 3 Defibrinated blood, 'which has been exposed 

 to the air for a period of twenty-four hours, is sealed in narrow glass 

 tubes (vaccine tubes answer well), and these tubes are then placed in 

 the incubator and kept a temperature of about 37 0. for some days. 

 On opening the tubes and emptying their contents into a watch glass or 

 on a glass slide, and allowing some time for evaporation to take place, 

 crystals of extraordinary size are obtained. 



4. Max Schultzes method* Defibrinated blood is heated (on a warm 

 stage, in the case of a microscopic preparation) to a temperature of 60 F., 

 when the corpuscles dissolve and the blood becomes lake-coloured ; it 

 is then allowed slowly to cool and to evaporate. This method may be 

 employed with large quantities of blood, and Preyer 5 found that by no 

 other method did he obtain as fine and as large crystals from horse's 

 blood. 



In addition to the four methods which have been above described as 

 most conveniently yielding crystals of oxyhaemoglobin, when these are 

 desired on a small scale, there are many others which have been employed, 

 and which occasionally give good results. 



Thus Ilollett 6 found that when induction shocks were passed through 

 blood, it became lake-coloured and yielded crystals of haemoglobin, and 



1 Ztschr.f. rat. Med., 1851, S. 185. 



2 "Versuclie und Beobachtungen am Blute," Sitzungsb. d. Jc. ATcad. d. Wissensch.. 

 Wien, 1863, Bd. xlvi. S. 77. 



3 Arch.f. d. ges. PhysioL, Bonn, 1878, Bd. xvi. S. 421. 



4 " Ein heitzbarer Objecttisch und seine Verwendung bei Untersuchungen des Blutes," 

 Arch.f. mikr. Anat., Bonn, 1865, Bd. i. S. 31. 



5 "Die Blutkrystalle," S. 23. 



6 Sitzungsb. d. Jc. Akad. d. Wissensch., Wien, 1852, Bd. xlvi. S. 75. 



