208 (lIF.MlSTh'Y OF Tin: IMMIMTY NEACTIOXS 



greater concentration oi" enzymes may destroy them. Fundamentally 

 serum bacteriolysis and phagocytosis seem to he the same — in each case 

 specific antibody sensitization prepares the hacterium for lysis by 

 enzymes, either inside or outside the cells that fur)iish the lytic enzyme. 

 As yet nothing- is known concerning the cliange brought about in 

 the bacteria by the opsonin, although it has been established that it 

 is the bacteria that are modified and not the leucocytes. The chemical 

 nature of the opsonins is likewise unknown, except that they may 

 combine with certain inorganic ions and are then inert (Hektoen and 

 Ruediger) ,-*^ since addition of CaCL, BaCl., SrCL MgCU, K.SO^, 

 NaHCO.j, sodium oxalate and potassium ferroc^-anide, inhibit the 

 opsonic effect of serum. On the contrary, calcium salts stimulate the 

 phagocytic effect of leucocytes, salts of barium and strontium being 

 inactive.*® In common with other immune bodies, opsonins are 

 thrown down in the soluble serum globulins.^" They are very sensitive 

 to acids and alkalies, being destroyed by a concentration of n/^ and 

 their maximum effect is at the neutral point.** However, treatment of 

 either the bacteria or the leucocytes with very weak acids or alkalies, 

 increases the rate and amount of phagocytosis (Oker-Blum ).•*'■* Op- 

 sonins may be developed by immunizing against substances practically 

 free from protein, e. g., melanin granules. ""^ Injection of nuclein 

 preparations may increase the amount of opsonin present in the 

 blood. °°^ Cholesterol in excess diminishes phagocytosis, but appar- 

 ently through its action on the leucocytes.^'"' Both the sensitization 

 of bacteria and their ingestion by leucocytes, either with or without 

 sensitization, take place in accordance with the laws regulating an 

 adsorption process (Ledingham,"'"'' Schiitze*"). 



THE MEIOSTAGMIN REACTION 



Reaction of antigens with their specific antibodies results in lower- 

 ing the surface tension of the solution in which the reaction occurs, 

 which may be demonstrated by counting the number of drops of the 

 fluid per minute, under constant conditions. Ascoli and Izar ^^ 

 worked out methods for practical application of this phenomenon, 

 giving it the name of "meiostagmin reaction," from the Greek, mean- 

 ing ''small drop." The numl)er of drops from a stalagmometer is 

 counted, and an increase of two or more per minute is considered a 



45 .Tour. Infect. Dis., 190.'') (2), 120. 



4" llamburfjer, Biochem. Zeit., 1910 (24), 470; 1910 (2()K M. 



47 See Simon et al., Jour. Exp. ]\Ied., 1906 (8), G51; I li'iiiciiiaiin ami (lato- 

 wood, .lour. Infcc-. Dis., 1912 (10), 410. 



48 No-ruclii, .lour. Kxp. Mod., 1907 (9). 4.)4. 



49 Zeit. linnnuiitiit., 1912 (14), 48.5; Sdiiitzo. Jour. llv>:., 1!>14 (14). 201. 

 ■'-n Lcdiii^haiii. Zeit. liinnunitiit., 1909 (.3). ll'.i. 



■"'Oa lU'dson, .lour. Patli. and I5act., 1914 (19). I'.H. 



cob Dewev and Nu/.um, .Tour. Infect. Dis., 1914 (hi). 472. 



•"•oo.Tour.'lIyff., 1912 (12). 320. 



51 :\Iiincli. nied. Woch., 1910 (57), (12. 182 and 403. 



