98 VACCINE AND SERUM THERAPY. 



carbonic acid, contain none of the anti-toxins. In this same 

 year Belfanti and Carbone found that with the globulins precipi- 

 tated by magnesium sulphate, diphtheria anti-toxin is thrown 

 out. Atkinson, in 1901, and others since then, have shown that 

 during immunization the serum-globulin content of serum in- 

 creases. Gibson and Banzhaf, however, have found that the 

 increase in serum-globulin is not necessarily associated with the 

 accumulation of anti-toxin in the blood. Early in 1906 Gibson, 

 working in the Research Laboratories of the Department of 

 Health of New York City, reported practical methods for con- 

 centrating and purifying diphtheria anti-toxins. According to 

 this method, by half saturation of anti-toxic serum with ammon- 

 nium sulphate, the globulins, nucleo-proteids, and similar sub- 

 stances are thrown out. These contain the immune bodies. The 

 precipitate is again dissolved in a saturated solution of sodium 

 chloride. Now only the anti-toxin fraction and some of f he 

 globulins are in solution. After filtration, acetic acid is added 

 to the filtrate to precipitate the anti-toxic globulins which are 

 then filtered off, dried with paper, dialyzed, neutralized and again 

 dialized for several days. After dialysis the solution is made 

 isotonic by the addition of sodium chloride. The sulution is then 

 filtered through a Berkefeld filter to remove any bacteria that 

 may be present and chloroform added as an antiseptic. This 

 method has been attempted for the various immune sera, but up 

 to the present time it is profitable only for the concentration of 

 diphtheria and tetanus anti-toxins. Recently Banzhaf has found 

 that more concentrated anti -toxin may be obtained by heating 

 the serum to 57 for some hours before separating the anti-toxic 

 globulins. By Gibson's method the concentration is increased 

 from three to five times, while by Banzhaf 's from eight to ten times. 

 By the use of concentrated and refined serum the consti- 

 tutional disturbances and rashes are somewhat less frequent and 

 not as severe. The principle advantage of the product obtained 

 by these methods, however, lies in the fact that a large amount 

 of immune substance can be injected in small amounts of material. 



DRIED IMMUNE SERUM. 



Relatively recently, immune sera, especially anti-diphtheritic 

 and anti-tetanic sera, have been dried after concentration and 

 refinement. It was mentioned earlier that when serum is dried 



