428 



Mr. H. E. Dean. 



[Oct. 13, 



The above experiment shows that sensitised cells remove from a middle- 

 piece solution the substance which causes their agglutination. To demon- 

 strate the manner in which this substance was removed it was decided to 

 employ a solution of the constituents of the corpuscles in distilled water. One 

 cubic centimetre of thoroughly washed sheep corpuscles was laked with 

 9 c.c. of distilled water. The solution of corpuscles was made up to the usual 

 saline content by the addition of 10 c.c. of 1*7 per cent, sodium chloride 

 solution. After filtering many times through filter paper a perfectly clear 

 solution was obtained, representing a 1 in 20 solution of red corpuscles in 

 normal saline. 



The following mixtures were then prepared : — 



Tube. 



Solution of 



laked 

 corpuscles. 



Antiserum, 

 rabbit v. sheep 

 cells, 1 in 200. 



Normal saline 

 solution. 



Solution of 

 middle-piece 

 1 in 10. 



Normal saline 

 solution. 



1 

 2 

 3 

 4 



5 

 5 

 5 



c.c. 

 5 



5 

 5 



c.c. 

 5 

 5 



10 

 10 



10 



10 



In tube 1 5 c.c. of the solution of corpuscles was added to 5 c.c. of the 

 diluted antiserum. In the control tubes 2, 3, and 4 the ingredients indicated 

 in the first three columns were mixed. The volume in each tube was then 

 10 c.c. All the tubes were allowed to remain for one hour at room tem- 

 perature. They were then examined and the contents were found to be 

 absolutely clear. To tubes 1, 2, and 4 were then added 10 c.c. of the 1 in 10 

 middle-piece solution ; to tube 3 was added 10 c.c. of normal saline solution. 

 All four tubes were then incubated for four hours at 37° C, and then placed 

 for 12 hours in a cool chamber at about 8° C. Tube 1 was then found to. 

 contain a small but definite white flocculent deposit. The three control tubes 

 remained absolutely clear. 



This experiment with unimportant variations in detail was several times 

 repeated. In every case the tube which contained antigen, antibody, and 

 middle-piece solution contained a precipitate. The control tubes contained no 

 precipitate. • 



Results obtained by nddiny Midi He- Pi eve Solution, to a Mixture of a Normal 



Serum with its Homologous Antiserum. 

 It has been shown that sensitised red oorpuscles are agglutinated by middle- 

 piece and that in the process of agglutination the substanee which produces 



