w, AGGLUT1N1NS 37 



' . c 



salts. For agglutination to take place he con- 

 siders it is as necessary as the agglutinin and agglu- 

 tinable substance. He believes that salts play an 

 active part in the process, a conception which is 

 contrary to Bordet's, that the absence of salts 

 offers only a physical impediment to agglutination. 

 Friedberger does not consider that the salts act 

 chemically for he found agglutination to take place 

 in the presence of grape sugar, asparagin, etc. 



In view of the fact that the protoplasm of the 

 body and the albuminous constituents of serum have 

 a close relationship to, or really are, colloids, inves- 

 tigators have studied certain reactions which occur 

 among the colloids with the expectation that these 

 would throw some light on the reactions of proto- 

 plasm and of serums, 



Colloids diffuse very slowly and exert little or no 

 osmotic pressure, supposedly because of the large 

 size of the particles. They do not conduct elec- 

 tricity, but the particles react to the electric current 

 by alterations in the direction of their motion (i.e. 

 toward the positive or the negative pole), and, 

 moreover carry electric charges themselves. 



The features of colloids which bring them into 

 relation with the subject in hand are their coagul- 

 able nature in certain instances and the fact that 

 their particles may be agglutinated or precipi- 

 tated by the addition of minute amounts of salts 

 (electrolytes). This of course is entirely analogous 



