TOXINS AND ANTITOXINS 



43 



pseudo-globulin, which constitutes about 78 per cent, of the serum 

 protein. This fact is taken advantage of in the so-called concentra- 

 tion of antitoxin, in which the pseudo-globulin is thrown down by 

 the addition of ammonium sulphate. Heinemann states that pseudo- 

 globulins may be broken into fractions, one of which contains the 

 antitoxin in highly concentrated 

 form, thus making the bulk even 

 smaller than by the use of pseudo- 

 globulin. The precipitate is col- 

 lected, dialyzed free of salt, and 

 taken up in water, the final volume 

 being considerably less than the 

 original amount of serum, there- 

 fore containing a greater number 

 of antitoxic units per c.c. than the 

 whole serum. This does not mean 

 that the antitoxin is necessarily a 

 globulin, for it resists trypsin diges- 

 tion in greater degree than does 

 globulin. It is, however, an elec- 

 tro-positive colloid. Antitoxin is 

 not thrown down in indifferent 

 precipitates, and in this respect dif- 

 fers from the enzymes, nor does it 

 operate in the same quantitative re- 

 lations as enzymes. The large size 

 of the antitoxin molecule is indi- 

 cated by the famous Martin and 

 Cherry experiment, which showed 

 that if toxin and antitoxin are 

 mixed and passed through gelatin 



filters the toxin appears first. The PIG. i. Apparatus for filtration through porce- 

 Same point Was brought OUt by ^in of small quantities of material. ] 



Arrhenius and M a d s e n , who 

 showed that toxin diffuses ten times 

 more rapidly than antitoxin. Anti- 

 toxin is injured by moist heat of 60 to 70 C, destroyed by moist heat 

 of 100 C., and by dry heat of 140 C. 



The influence of temperature on antitoxin is of the utmost prac- 

 tical importance in regard to its preservation for therapeusis. 

 Anderson has estimated the yearly deterioration at different tem- 

 peratures as follows : 



rubber tube and the suction apparatus must be 

 inserted a small trap to prevent entrance into the 

 flask of water when suction is released. The trap 

 is a salt neck bottle with an inlet and outlet tube 

 through a rubber stopper. 



Temperature 



5C. 



Yearly deterioration 

 20 per cent. 

 10 per cent. 

 6 per cent. 



