COMPLEMENT-FIXATION TEST IN CONTAGIOUS ABORTION 513 



3. A known negative serum should be tested in the same manner. 



4. The antigen control, which at this stage contains the dose of 

 antigen, complement, and saline solution. 



5. The hemolytic control, which at this time contains but 1 c.c. of 

 complement plus saline solution. 



6. The corpuscle control, containing 1 c.c. of corpuscle suspension 

 and 3 c.c. of saline solution. This tube should be plugged with cotton. 



All tubes are gently shaken and incubated for an hour in a water- 

 bath at 38 C. or in a refrigerator at 8 to 12 C. for four to six hours or 

 over night, after which 2 units of hemolytic amboceptor and 1 c.c. of 

 corpuscle suspension are added to all except the corpuscle control. 

 The tubes are gently shaken and reincubated in a water-bath for an 

 hour or two, depending upon the hemolysis of the controls. Primary 

 incubation in the refrigerator is especially recommended. 



The controls are first inspected. They should all show complete 

 hemolysis, except the first three tubes of the positive serum series and the 

 corpuscle control. Inhibition of hemolysis in the first three tubes of 

 the series containing the unknown serum indicates a strong positive 

 reaction. Complete hemolysis in all tubes indicates a negative reaction. 

 Partial hemolysis in the first three tubes indicates a partially positive 

 reaction. If the serum control or antigen control tubes should show in- 

 hibition of hemolysis, these were probably anticomplementary and the 

 test should be repeated. 



COMPLEMENT-FIXATION TEST IN CONTAGIOUS ABORTION 

 It is now generally conceded among veterinarians that the Bacillus 

 abortus of Bang is the specific cause of contagious abortion of cows. 



Evidence is gradually accumulating to show that an organism be- 

 longing to the paratyphoid group is frequently the cause of a similar 

 condition among mares (Kilbourne and Smith, 1 Liguierer, 2 Liguierer 

 andZabala; Good; 3 VanNeelsbergen; 4 de Jong; 5 Meyer and Boerner) 6 . 

 Meyer and Boerner, who have studied this bacillus with particular care, 

 classify it with the paratyphoid-enteritidis group (Bacillus aborti equi). 



1 United States Department of Agriculture, Bulletin No. 3, 1893, 49 and 53. 



2 Rec. Med. veterinaire, Ixxxii, 1905. 



3 Kentucky Agriculture Exper. Station Bulletin No. 165, 1912. 



4 Tijdschrift, v. Veeartsenijk., xxiv, 1912. 



5 Archiv. f. Wissenshaftl. u. prak. Tierheilkunde, xxv, 1900. 



6 Jour. Med. Research, 1913, xxix, No. 2, 325. 



33 



