SEROLOGY MANUFACTURE AND USE OF SERA AND VACCINES 267 



c. The second precipitation product is treated with a saturated salt 

 solution which dissolves the antitoxin globulins. The solution is then filtered. 



d. To the filtered solution 2.5 per cent, of acetic acid is added which 

 again precipitates the globulins on the filter paper where it is partially 

 dried by means of filter paper and towels pressed upon the mass. 



e. The partially dried material is placed in a dialyzing bag and sus- 

 pended in a water current, for several days. This removed the salts by 

 osmotic action and at the same time the globulins enter into solution 

 within the bag. 



f . A preservative is added to the liquid which is then passed through 

 a Berkefeld filter. Some physiologic salt solution is also added. This is 

 the final product. 



g. After being tested bacteriologically to make sure that it is not con- 

 taminated, it is standardized as described under diphtheric serum. 



The above process removes the following non-active substances: 

 serum albumins, lecithin, cholesterin, traces of bile salts and acids, blood 

 salts and the non-antitoxic globulins. The dosage of the concentrated 

 antitoxin is less than that of the non-concentrated serum and it keeps 

 longer. For the manufacture of the concentrated diphtheria antitoxin 

 the returned serum is generally employed, that is serum which has ex- 

 ceeded the time limit of use. 



3. Antitetanic Serum 



This is prepared similarly to antidiphtheric serum. The tetanus 

 bacilli are grown in bouillon, in the absence of oxygen, since tetanus germs - 

 are anaerobic. The growth is then killed, filtered out and the clear toxic, 

 germ-free bouillon filtrate is utilized in the immunization of the horse. 

 Small doses, usually mixed with some antitetanic serum, are administered 

 at first and gradually increasing the amount as the horse can stand it until 

 large quantities are given, even as much as 700 or 800 cc. After some 

 months the horse is bled in the same manner as for antidiphtheric serum, 

 the serum is separated and bacteriologically tested in the same way. 



The unit of tetanus antitoxin is that quantity of antitetanic serum 

 which is necessary to completely neutralize 1000 fatal doses of tetanus 

 toxin for a 250-gram guinea-pig. 



Antitetanic serum has not been a marked success as a curative agent. 

 Its greatest usefulness appears to be as a prophylactic, for which purpose it 

 should be given early, as soon as the injury (cut, gunshot wound, abrasion) 

 has occurred. 



The following are the more important antibacterial sera. A fuller 

 description of the processes of manufacture is omitted as that is a matter df 

 no special importance to the pharmacist. Furthermore, manufacturers do 

 not, as a rule, disclose full details of manufacture. 



