history. Two of them were inoculated by intravaginal application of pure cultures, and two by intravaginal application of pieces of afterbirth from aborting cows. No abortion resulted in any of the cows and at slaughter 19 to 29 days after inoculation, there was no evidence of the disease. This result was surprising, as Brauer had induced abortion by the second of the above-mentioned procedures in from 9 to 21 days, Lehnert in from 12 to 20 days, and Trinchera in 9 to 13 days. The authors thought that the animals may have been immune on account of a previous attack of the disease, or that possibly the interval between innoculation and slaughter (19 to 29 days) may have been too brief for the disease to have developed. For the next experiment two cows were purchased from a region where abortion was unknown. Pregnancy began January 14 and January 16, 1896. On April 14, a rich culture of the abortion bacillus was injected well up into the anterior end of the vaginal canal of each of these cows. The inoculation was repeated in the same way on May 23, and again on June 4. One cow aborted June 24, the fetus evidently having been dead some days. The abortion bacillus was isolated from the afterbirth. The other cow showed the signs of impending abortion on June 23, and was slaughtered on June 24. The condition inside the uterus resembled in every respect that observed in the cow from which the original culture had been isolated, and the bacillus was present in pure culture. In these cows the disease had appeared 10 weeks after the first inoculation. A third cow was inoculated by intravaginal application January 19, 1897, and subcutaneously March 6, in both instances with pure cultures of the bacillus. Premature delivery of a living calf occurred April 9, 80 days after the first inoculation. Abortion was also caused in sheep by intravaginal application and by intravenous injection of pure cultures. Inoculation by the latter method proved to be more certain in these animals, and the incubation period after intravenous injection was only 7 days in one case and 12 days in another. Intravenous inoculation of a mare resulted in a premature delivery after 28 days. In all these cases the bacillus was recovered from the afterbirth.

In 1902, Preisz at Budapest isolated the same bacillus from two cases of contagious abortion in cows. He confirmed the findings of Bang in respect to the oxygen requirements of the organism, and was able to obtain cultures by a variety of methods on ordinary media. Apparently his cultures were less vigorous than those of Bang, for they soon died out, their resistance to germicides was slight, and all his inoculations into animals, including two pregnant cows, two pregnant guinea pigs, and one pregnant rabbit, as well as a number of other small animals, were without positive result. Preisz named the organism "Corynebacterium abortus endemici (s. infectiosi)."

In 1908, Nowak at the University of Krakau in Austria made a very important contribution to the study of this disease. He found the culture method of Bang and Stribolt very useful for the identification of the organism when obtainable in pure culture, and when the contaminating bacteria were few in number. When other bacteria were numerous, as is frequently the case in material obtained for examination, he found this method difficult. The pyrogallol method of Preisz also proved to be unreliable in his hands. Eventually he devised a method of plate culture which proved to be very useful. Ordinary agar was melted and cooled to 50° C. then mixed with about one fourth its volume of naturally sterile blood serum, and poured into sterile Petri dishes where it was allowed to solidify. The piece of placenta or other material to be examined was then streaked over several of these plates in succession, and the plates were incubated for 24 hours at 37° C., to allow contaminating bacteria to develop. The plates were next placed in a glass jar together with a culture of Bacillus