EXPERIMENT STATION BULLETINS. 269 



growth was usually found to be exceedingly slow. By adding one per 

 cent, starch or one per cent, dextrose or both to the medium, it was 

 found that the growth would progress more rapidly. Later it was found 

 that excellent growth could be obtained by employing spleen and liver 

 media in place of beef. The composition of these media does not differ 

 from that of ordinary beef agar except for the substitution of liver and 

 spleen in the infusion in place of beef. The amount of spleen or liver 

 added per liter of water is the same as that of beef. It was found that 

 the spleen media were improved by the addition of one per cent, starch, 

 or one per cent, dextrose or both; while the liver agar did not require 

 the addition of carbohydrates. 



In order to compare the value of various media for the cultivation 

 of Bad. abortus three laboratory strains were selected and incubations 

 made as shown in Table I. 



Strain "W" has been in the laboratory for several years and has al- 

 ways grown well on artificial media. Strain 15 was isolated in 1916 

 and grew very poorly for six months or more previous to employing 

 spleen and liver media. 



Strain XX was isolated in the spring of 1919 and has grown about as 

 well as the average of our laboratory strains. 



SUMMARY. 



Liver and spleen media have been employed in this laboratory by 

 the writer for more than six months and have given good results. Strains 

 of the abortion bacillus have been isolated more easily by the aid of these 

 media. As is shown in Table I, there is very little or no difference be- 

 tween plain liver media and spleen media containing carbohydrates in 

 the form of starch or dextrose. 



Some strains have been found to possess certain idiosyncrasies, thus 

 making it necessary to employ various media in order to find one that 

 will produce the desired results. In some cases it may be necessary to 

 make the first transplant from a newly isolated strain into broth, before 

 being able to grow the organisms efficiently on agar slants. 



The employment of B. suhtilis as a means of producing anaerobiosis 

 was found to be unnecessary as the use of a glass jar from which the air 

 can be partly exhausted with a suction pump has given satisfactory 

 results. 



REFERENCES. 



(1). .Giltner, Ward. 



1912. Infectious Abortion in Cattle. 



Proceeding of Am. Yet. Med. Ass'n, 1912, 315-355. 



(2). Giltner, Ward. 



1917. Keport of Bacteriologist, Mich. Agr. Expt. Station. 



(3). Smillie, E. W. 



1918. An Improvement in the Method of Isolation and Kecov- 



eriug of Bacillus of Cattle Abortion Through Guinea 

 Pigs. 

 Jour. Exp. Med., Vol. XXVIII, No. 5, Vol. 1, pp. 585, 605. 



(4). Smith, Theobald. 



1919. The Bacteriology of Bovine Abortion With Special Refer- 



ence to Acquired Immunity. 

 Jour. Exp. Med. Vol. XXX, No. 4, pp. 325-339, Oct. 1. 



