66 



LABORATORY COURSE IN SERUM STUDY 



D 



The students in charge of the immune rabbits should test at the same 

 time the samples of serum which were obtained from the rabbits before 

 they received their first injection and which have been stored in the 

 ice box meanwhile. In this case one tube of undiluted serum should be 

 tested, one of a 1-10 dilution, one of 1-50. It is not necessary to test 

 higher dilutions. 



II. MACROSCOPIC METHOD OF PROSCHER 



Take four glass saltcellars. In the first place 0.5 c.c. of 1-10 dilu- 

 tion of serum used in the first experiment ; in the second 0.5 c.c. of 1-500 

 serum ; and in the third 0.5 c.c. of 1-2000 dilution ; in the fourth 0.5 c.c. 

 of salt solution. To each add 0.5 c.c. of typhoid suspension. The salt- 

 cellars are stacked one on top of the other and placed in the incubator 

 for one hour. At the end of this time they are taken out and may be 

 studied under low power of the microscope. A record is made of the 

 amount of clumping in each preparation. 



HI. THERMOSTABILITY OF AGGLUTININS 



The agglutinins like the bactericidal sensitizing substance are 

 resistant to moderate heating but they do not require the reacti- 

 vation by the heat-sensitive alexin which is present in normal 

 serum. They are, however, destroyed by exposure to tem- 

 peratures of from 70 to 80, in which respect they also resemble 

 the sensitizing substance. 



In each of three agglutination tubes place 0.5 c.c. of a 1-10 dilution 

 of the immune serum. Place one tube in a water bath at 56 C. for one 

 half hour. Place a second tube in a water bath at 73 C. for one half 

 hour. Reserve the third tube as a control. After heating add 0.5 c.c. of 



