PROTEIDS OF SERUM. 145 



is less or greater than that of the blood. Change 

 the SS accordingly, until the drop neither rises nor 

 falls during the first moments after ejection. 



The S.G. of blood varies. It is highest in the male sex 

 and at birth ; is lowest from the ages of 35 to 45 years. 

 Falls with hunger, pregnancy, food and drink. 



Proteids of Serum. 



Blood serum. Contains approximately 7 p>c< proteids consisting of 

 4 parts serum-albumin and of 3 parts serum-globulin (para-globulin). 



Sheep or ox blood is allowed to clot in the vessel into which it 

 has been run from the animal in the slaughter house ; on standing the 

 clot contracts and squeezes out the serum. If any water be present 

 in the vessel at the time the blood is run in the serum will be tinged 

 with the colouring matter of the corpuscles. 



Dilute 10 cc serum to 70 cc (= 1 p - c - proteid approximately) 

 with water and repeat the reactions performed on egg 

 albumin. 



Difference between egg and serum, albumin. 



Serum albumin is more soluble in nitric acid. Egg 

 is coagulated by ether in a neutral reaction, whilst 

 serum is not. 



Relative sensitiveness of some of the proteid reactions. 



Dilute some of the above reputed 1 p - c - solution to 

 50 cc with normal saline = Ol p - c - solution (a); repeat this 

 operation successively with 5 cc of (a) = O01 p>c - (b) 5 cc 

 of (b) = 0-001 p - c - (c) ; 5 cc of (c) = 0-0001 p - c - (d) ; 5 cc of 

 (d) = 0-00001 p - c - (e). 



Take 5 tubes, number them from 1 to 5, place in each 

 of them 2 cm of HNO 3 . Do this by means of a pipette 

 so as not to wet the sides of the tubes. Next, with the 

 pipette pour two volumes of proteid solution (e) upon 

 the acid in tube No. 5, being careful to avoid mechanical 



