CHAP. IV.] THE BLOOD. METHODS OF KESEARCH. 189 



boiled. The flocculent precipitate is then collected on a filter and 

 washed with a mixture of 10 parts of alcohol and 1 part of water, 

 then with absolute alcohol and ether. It is then treated as the 

 precipitate obtained by process a. 



Determina- This can only be done in the case of the serum 



being absolutely colourless and transparent. 



^he amount of albumin per gramme of solution will 

 be found by the formula 



a 



"^Wxl 



where a indicates the rotation observed and I the length of the tube. 

 The results are however only approximative. 



Determination of the amount of Fibrinogen contained in Liquor 

 Sanguinis. (Frederique's method a .) 



If it be desired to determine the amount of fibrinogen in liquor san- 

 guinis, the liquid, which has been kept from coagulating by exposure 

 to cold, or by the addition of magnesium sulphate, is heated to 60; 

 the precipitate is allowed to subside, washed by decantation with a 

 per cent, solution of sodium chloride, and then thrown on a small 

 weighed filter. The filter is washed with distilled water, then with 

 alcohol, dried at 110 C., cooled under an exsiccator, and weighed 

 between watch-glasses. The filter and contents may be afterwards 

 ignited and the weight of ash deducted. 



Determination of the amount of Serum-globulin in the Serum. 



Two methods may be employed, which give however entirely 

 different results; the second is alone reliable.- 



Schmidt's a . Serum is placed in a dialyser, the water around 



method. which is frequently renewed. After about 48 hours a 



stream of C0 2 is passed through the contents of the dialyser. The 

 precipitate which has formed is collected on a weighed filter, 

 washed, dried, and weighed. 



Hammar- ^ 5 C-C> o f serum are diluted with 25 c.c. of satu- 



iethod 3 ratec * somtion of magnesium sulphate and then treated 



with powdered magnesium sulphate. The fluid is stirred 



from time to time and the salt added to saturation. After at least 



24 hours, it is filtered ; the precipitate is collected on a filter 



moistened with saturated solution of .magnesium sulphate; the 



1 Hoppe-Seyler, " Bestimmung des Eiweissgehaltes an Blutserum verm. Polarisa- 

 tion." Yirchow's Archiv, Vol. xi. p. 547. 



2 L. Frederique, "Becherches sur la constitution du Plasma sanguin." Travail 

 du Laboratoire de Physiologie de VUniversite de Gand et du Laboratoire de Physiologic 

 de la Faculte des Sciences de Paris, 1878. 



3 Hammarsten, " Ueber das Paraglobulin. " Pfluger's Archiv, 1878, p. 413. 



