278 ■ STATE BOARD OF AGRICULTURE. 



"Ill order io throw more light upon tlie time of the appearance of anti- 

 bodies after an infection or immunization, two calves were injected with 

 suspensions of live Bact. abortus organisms. The time of the appearance 

 of the antibodies was then noted. The results are summarized in Table 

 I. 



"It is evident from the data in Table I that the time of the appearance 

 of antibodies depends upon the amount of material injected. One must 

 take into consideration tliat the amount of material injected into the 

 animals in this experiment is many times larger than that which would 

 enter the body when exposed uaturally to infectious material. There- 

 fore, one would expect the antibody formation to take place more slowly 

 as the result of natural infection. 



"Experiments to determine the length of time Bact. abortus survived 

 when introduced into the vagina of cows and the sheath of bulls are de- 

 scribed as follows : 



"Five cubic centimeters of a suspension of live Bact. abort us were 

 placed in a gelatin capsule and introduced far up into the vagina of 

 three cows. Swabs were made from the vagina twenty-four, forty-eight 

 and seventy-two hours after introducing the material. The swabs were 

 plated out immediately after being made. Bact. abortus was not in a 

 single instance isolated from the vaginas treated in the above manner. 



"Similar experiments with two bulls w^ere carried out by gravitating 

 twenty cubic centimeters of a live suspension of Bact. abortus into the 

 sheath. Swabs were made and plated out in the above described manner. 

 Bact. abortus was never isolated from the sheath. 



"These experiments serve to demonstrate that, under normal condi- 

 tions, Bact. abortus will not establish itself in the vagina of cows or the 

 sheath of bulls. 



"A comparative study of different strains of Bact. abortus was made. 

 "Morphology and staining characteristics : Apparently no difference. 



"Pathogenic characteristics : Apparently no difference. 



"Pathogenic and antigenic properties : The present data concerning 

 this study reveal some very interesting facts. The results, liowever, 

 have not been completed owing to the death of so many of the experi- 

 mental guinea pigs. The results will be published at a later date. 



"Longevity studies of Bact. abortus: Into sus])ensions of eleven dif- 

 ferent strains of Bact. abortus in sterile physiological salt solution were 

 placed small pieces of sterile wool, linen and silk cloth. The pieces of 

 cloth were removed from the suspension of bacteria after they had be- 

 come uniformly saturated and placed in sterile petri dishes. The dishes 

 were kept in a well lighted room without direct sunlight. From day 

 to day, pieces of each different kind of cloth were removed from the 

 dishes and smeared on agar plates. The appearance of colonies was 

 noted under aerobic and anaerobic conditions. None of the eleven 

 strains of Bact. abortus was isolated from the wool or from the silk 

 cloth after tAvo Aveeks. Two of the strains Avere able to survive on linen 

 cloth for four Aveeks. 



"The experiments Avith sterile soil, sand plus soil solution, hay and 

 tap water Avere conducted in a manner similar to the above. The ma- 

 terials AA'ere j^laced in sterile flasks, and to each Avas added one cubic 

 centimeter of a suspension of Bact. abortus in sterile phj^siological salt 

 solution. Each of the flasks of material was shaken from day to day 

 and plated out to determine the presence of Bact. abortus. The follow^- 



