ABSTRACTS 359 



intravenously at the rate of 7 cc. per pound of body weight into immunes 

 gave satisfactory results in the production of potent antisera when 

 these sera were tested on susceptible shoats infected with 2 cc. of virus. 

 The conclusions are reached that an immune serum may be produced 

 and used more economically when mixed salt virus and blood virus 

 are employed and injected by the intravenous method, since the total 

 volume of available virus solution is raised by this procedure from 75- 

 80 per cent.— P. B. H. 



Experiments to Determine the Relative Value of Trikresol and Carbolic 



Acid in the Preservation of Hog Cholera Serum. John Reichel. 



(Mulford's Vet. BuL, 1916, 7, 61-64.) 



Carbolic acid is generally used as the preservative of hog cholera 

 serum, even though comparatively little is known of its value as a 

 germicide in such a product as hog cholera serum in the form of de- 

 fibrinated blood as originally prepared by Dorset, McBryde and Niles. 

 That carbolic acid itself has little or no effect on the potency of the 

 product is conclusively established. 



Whether trikresol is equally harmless and as effective as a preservative 

 remains to be shown. 



Hog cholera serum as generally prepared is not sterile. The blood 

 as drawn from the serum-producing animal is invariably contaminated 

 and subsequent handling in defibrination allows for additional con- 

 tamination, up to the time the preservative is added, varying in degree 

 with the care exercised in its preparation. Even though it is possible 

 to obtain sterile blood from a serum-producing hog, this can only be said 

 of experimental trials and in producing hog cholera serum defibrinated 

 blood, in a practical way, the question of sterility must be entirely 

 sacrificed. 



Carbohc acid will not sterihze this contaminated product and the 

 question naturally arises "does it hold the organisms in check whether 

 present in large or small numbers?" 



The writer observes that: 



1. Carbolic acid must be used in less than 0.75 per cent to avoid 

 changes in the physical appearance of hog cholera serum defibrinated 

 blood. 



2. Trikresol must be used in less than 0.6 per cent for the same reason. 



3. Carbohc acid added in amounts up to 0.75 per cent to lightly or 

 heavily contaminated defibrinated blood first caused a decrease in the 

 number of bacteria followed by an increase exceeding the first bacterial 

 count. 



4. Trikresol with a carbolic acid coefficient of 2.87 added in 

 amounts up to 0.6 per cent was also followed by a decrease, then an 

 increase practically equal to that which occurred in the carbolized 

 samples. 



5. All of the controls, without any preservation, showed an increase 

 in the bacterial count from the time the samples were first set aside 

 along with those to which a preservative had been added. This 



