164 



LABORATORY COURSE IN SERUM STUDY 



in the preliminary test the tube containing 0.5 c.c. of trypsin solution 

 was completely dissolved this series of tubes should contain 0.5, 0.75, 1.0, 

 1.25, 1.5 and 2.0 c.c. respectively. Sufficient salt solution is added to 

 bring the volumes up to 2.0 c.c., and 2.0 c.c. of casein solution added 

 to each tube. The tubes are incubated for one half hour and at the end 

 of this time the undigested casein is precipitated by the addition of a 

 few drops of the acetic acid solution. 



In the presence of carcinoma serum from \\ times to twice the 

 amount pf trypsin will be found necessary to completely digest the 

 casein that is necessary in the presence of normal serum. On the other 

 hand, in the serum which has been extracted with chloroform the anti- 

 try ptic activity will be found to have been almost completely removed. 



TESTING OF SERUM 



LESSON XXVI 

 NATURE OF NORMAL OPSONIN 



INTRODUCTORY REMARKS 



IN the early days of immunological investigation it was sup- 

 posed that phagocytosis depended upon properties inherent in 

 the phagocyting cell. More recent investigations, starting with 

 those of Metchnikoff, continued by Denys and Leclef and others, 

 and brought to focus by Wright and his associates, have shown 

 that in phagocytosis, at least when carried on by the polynuclear 

 cells of the circulating blood, it is a function of the cooperation 

 of serum and phagocyte. It has been found that the serum 

 so acts upon the bacteria that they are rendered more easily 



