CHAP. II.] THE BLOOD. 87 



These methods are not to be recommended. 



IV. The defibrinated blood of the dog is mixed with its own volume 

 of distilled water and the diluted fluid is treated with one fourth of its 

 volume of alcohol. The mixture is kept for 24 hours at a temperature of 

 0C. or below. The crystals which separate are dissolved in as small a 

 quantity as possible of water at 25 to 30 C., and the solution being cooled 

 to 00. a fourth of its volume of alcohol is added. 



It is better to place the fluid in a freezing mixture at a temperature 

 of- 10 to - 20 for 24 hours. The whole fluid then becomes filled with a 

 magma of crystals. The process of recrystallization may be several times 

 repeated. 



V. Blood is collected in a capsule and, having coagulated, is allowed to 

 stand undisturbed for some hours or, better still, for a whole day. The 

 serum is then decanted, the clot washed with water and cut into small 

 pieces, and these also are repeatedly washed with distilled water. When the 

 washings are no longer strongly precipitated by solution of mercuric chloride, 

 the pieces of clot are treated with water heated to 30 40 0., and the fluid 

 is filtered, the filtrate being collected in a cylinder surrounded by ice. A 

 known fraction of the red solution is then treated little by little with alcohol 

 (poured out of a burette), the fluid being continually stirred, until a slight 

 precipitate is formed. In this way is ascertained how much alcohol may be 

 added without a precipitate resulting. Having thus found out how much 

 alcohol would have to be added to the whole quantity of filtrate, a some- 

 what smaller quantity is actually added, and the fluid is placed in a freezing 

 mixture. After some hours crystals separate abundantly. As much water 

 has been employed in the process, the crystals can easily be filtered. 

 These are washed, first with water holding alcohol in solution and after- 

 wards with iced water. The crystals thus obtained may either be at once 

 used or be purified by further crystallization. At a temperature below 

 C. they can be dried in the air without decomposition. 



VI. Defibrinated blood is mixed with ten times its volume of a 

 solution of sodium chloride (made by diluting 1 volume of saturated 

 solution of NaCl with from 9 19 volumes of water), and allowed 

 to stand for one or two days in a cool place so as to allow of the 

 greater part of the blood corpuscles to settle. The supernatant liquid 

 is decanted and the corpuscles are placed with a little water in a 

 flask and then ether is added. After repeated agitation, the ether is 

 decanted, and the fluid is filtered through a plaited filter as rapidly 

 as possible. The filtrate is cooled to C. and treated with its volume of 

 spirits of wine ; the mixture is then maintained for some days at 5 or 

 - 10 C. The crystals which separate may be purified by recrystallization 1 . 



VII. 500 c.c. defibrinated dog's blood are treated with 31 c.c. of ether 

 and the mixture shaken for some minutes. It is then set aside in a 

 cool place. After a period varying from 24 hours to 3 days the 

 liquid has become converted into a thick magma of crystals. These 

 may be separated by placing in tubes and using the centrifugal apparatus. 



1 Hoppe-Seyler, Handbuch der physiologisch- und pathologiscTi-chemisclwn Analyse. 

 3* Aufl., 1870, p. 215. 



