280 STATE BOARD OF AGRICULTURE. 



DISCUSSION. 



The results obtained in series 1, 2, 3, 4, and 5 show that guinea pigs 

 infected with Bad. ahortits will react to the intradermal abortin test 

 while those which are treated with dead cultures only fail to react. The 

 results also indicate that the reaction is specific for Bad. abortus in- 

 fection since pigs subjected to treatments with live or dead typhoid 

 bacilli and live tubercle bacilli showed no reaction to Bact. abortus anti- 

 gens whatever. 



Tables 1, 2, and 4 and series 6 show that treatment with dead cultures 

 of Bact. abortus, whether administered before or after infection, does not 

 in any way prevent the development of cutaneous hypersensitiveness. 

 It is also evident that this treatment does not protect guinea pigs 

 against infection through injection or ingestion of live cultures if the 

 intradermal test is a true index of infection. In table 3, there is an 

 apparent discrepancy as pigs 82, 84, and 87 which were not intentionally 

 exposed to infection by the writer developed positive reactions to all 

 tests. This, however, may easily be accounted for as the two cages in 

 which these pigs were kept stood so close together that infection might 

 readily be carried from one cage to the other with dust or straw, which 

 the pigs might kick through the wire netting. The extreme susceptibil- 

 ity of the guinea pig to Bact. abortus infection is brought out by this 

 occurrence, as the amount of live culture introduced into the first cage 

 was very small. 



In analyzing the results obtained in table 4 and series No. 6 it will 

 be noticed that the four males placed with the females developed positive 

 reactions to all tests employed. This shows that guinea pigs, which 

 are infected with Bact. abortus, must discharge the organism, as the 

 infection of the males could be explained in no other way. Great care 

 was exercised not to bring any infection into these pens. The fact that 

 the treated (with lipo-vaccine) females listed in table 4 raised nine 

 young pigs betv\'eeu Oct. 4, 1919, and Jan. 6, 1920, while the females in 

 series 6, failed to raise a single one may be of some significance. Abor- 

 tions occurred in both pens due possibly to handling while in advanced 

 pregnancy, but as will be noticed from table 4, the pigs were not handled 

 very often. 



Many of the guinea pigs in these experiments became very much 

 emaciated and showed signs of paralysis or extreme weakness. This 

 was especially true of those pigs which were treated with dead cultures 

 subsequent to infection. 



The exact cause of this is not known, nor will an examination be at- 

 tempted at this time. Some of the females in series 6 and two or three 

 of those listed in table 4 showed signs of this same affection. Several 

 of them died, but those which recovered from the first effects of the 

 treatments developed no untoward after effects. 



In view of this work, it appears that the general condition of an 

 animal as regards infection and the condition of the uterus as regards 

 abortion do not correspond. If the lipo-vaccine was instrumental in 

 protecting the females, which gave birth to and raised the nine normal 

 pigs, against the harmful effect of the abortion bacillus, the local evi- 

 dence of this fact is the absence of abortions and the systemic evidence 

 the production of complement fixing and agglutination antibodies. The 



