NATURE OF COMPLEMENT. 277 



ject of antitoxins. The activity of the comple- 

 ment is again restored if the inhibiting salts are 

 precipitated by suitable chemicals. The salts are 

 used in such dilutions that they are largely ionized, 

 and Manwaring believes their inhibiting action is 

 due to the formation of compounds of the posi- 

 tive ions with the complement, resulting in such 

 substances as Ca-complement, Ba-complement, 

 etc. When the precipitating chemicals are added 

 the ions are freed from this combination, as a re- 

 sult of which the complement recovers its activat- 

 ing properties. It has not as yet been determined 

 whether variations in the salts in the fluids of the 

 body cause changes in resistance by their action on 

 native complements. 



The work of Ferrata, Hans Sachs and Teruuchi, Further AH- 

 Brand and Hecker has shown that complement Complement. 

 may be divided into two parts by the separation of 

 the albumin and globulin contents of the serum 

 containing it. 



Neither of these two parts alone has the power 

 to bring about hemolysis in corpuscles previously 

 sensitized by the addition of amboceptor. When 

 combined, however, hemolysis takes place as before 

 separation. 



Absorption of the globulin fraction takes place 

 when it is added to sensitized corpuscles, result- 

 ing in "Persensitized corpuscles" (Michaelis and 

 Skwirsky), which then undergo hemolysis on ad- 

 dition of the albumin fraction. The albumin 

 fraction, on the contrary, is incapable of being 

 bound by the sensitized corpuscles in the absence 

 of the globulin fraction. Brand therefore terms 

 the globulin fraction as complement "middlepiece" 



