THE DURATION OF PASSIVE IMMUNITY AGAINST TETANUS 



TOXIN 1 



By E. H. RuEDiGER 



{From the Section of Sera and Prophylactics, Biological Laboratory, 

 Bureau of Science, Manila, P. I.) 



In a previous communication ^ I reported that in guinea pigs 

 passive immunity conferred by antitetanic serum from horse is 

 of short duration, perhaps not longer than three weeks. 



The experiments to be reported are grouped under the follow- 

 ing three heads •• 



1. The duration of passive immunity in horse, after the injec- 

 tion of homologous antitetanic serum. 



2. The duration of passive immunity in guinea pigs after an 

 injection of antitetanic serum from horse, preceded by repeated 

 injections of antitetanic serum from horse. 



3. The duration of passive immunity in guinea pigs after an 

 injection of antitetanic serum from horse, preceded by repeated 

 injections of normal horse serum. 



EXPERIMENT NO, 1 



In September, 1911, three large, apparently healthy horses, 

 Nos. 1, 2, and 3, were obtained for this purpose. Horse 1 re- 

 ceived 1,500 units of antitetanic serum from horse injected sub- 

 cutaneously on September 9, 1911. Horse 2 received a sub- 

 cutaneous injection of 1,500 units of antitetanic serum from 

 horse on October 9, 1911. Horse 3 was used as control. 



On October 23, 1911, two weeks after horse 2 had received 

 the serum and six weeks after horse 1 had been inoculated with 

 serum, each of the three horses was inoculated subcutaneously 

 with about 50 standard doses of test toxin. 



Table I. 



No. of 

 animal. 



Anti- 

 tetanic 

 serum 

 units. 



Date. 



Tetanus 



toxin 



test 



doses. 



Date. 



Weeks 

 after 

 eerum. 



Result. 



Date. 



1 



2 



3 



1,500 

 1,500 

 none 



Sept. 11, 1911 

 Oct. 11,1911 



50 

 50 

 60 



Oct. 23.1911 



d<i 



do 



6 

 2 



Lived... 









Died.... 



Oct. 30,1911 









* Read before the Ninth Annual Meeting of the Philippine Islands Medical 

 Association, held in Manila from November 4-7, 1912. 

 *Bull. Manila Med. Soc. (1911), 3, 98. 



139 



