418 



STATE BOARD OP AGRICULTURE. 



actions, are the amounts and sources of the sera and virus injected 

 and the results of the treatment. 

 As for the agglutination reactions, it will be seen that 



6 or 12.25 per cent gave no reaction at a dilution of 1^ — 50. 

 5 or 10.20 per cent reacted at a dilution of 1 — 50. 



G or 12.25 per cent reacted at a dilution of 1 — 100. 

 G or 12.25 per cent reacted at a dilution of 1 — 125. 



7 or 14.28 per cent reacted at a dilution of 1 — 250. 

 19 or ?.8.77 per cent reacted at a dilution of 1 — 500. 



These results correspond quite closely to those secured with virus 

 blood. One might be tempted to qonclude that the influence of the 

 serum could not be detected in the agglutination reactions. It must be 

 borne in mind that the average weight of the pigs in Table III is only 

 35 lbs. and also that they received only 1 cc. of virus each. Now we 

 can make a fairer comi)arison of the agglutinative poAver of the blood 

 serum of pigs treated with hog cholera virus only, and with hog cholera 

 virus and serum simultaneiuisly. The summary on page 417 shows 

 that 7 pigs receiving 1 ( c. virus each and weighing on an average of 

 .')() lbs, reacted at an average dilution of 1-197. The average maximum 

 reaction at which agglutination occurred with the blood of 49 pigs 

 treiited with both serum and virus is 1-262. 



It will be of interest to note the difl:'erence in the agglutinative power 

 of the blood from the pigs that were protected by the serum and from 

 those that died. We have made this difference very readily jierceptible 



A comparatively much larger number of pigs that die fail to show 

 any agglutinative power in their serum, while the serum of a compara- 

 tively greater number of pigs that live gives a reaction at high dilution. 

 In other words, it seems that witli resistance or immunity we get in- 

 creased agglutinative power; with susceptibility or absence of immun- 

 ity, a less or no increase. This is in keeping with the deduction that 

 heavier or older pigs (which are well known to be more resistant to 

 cholera infection) have blood serum with a higher agglutinin content. 



We can find no relation between the amount of protective serum in- 

 jected into the pig and the production of agglutinins in the pig's blood. 



REACTIONS WITH THE BLOOD OF HYPBRIMJMUNIZED PIGS. 



This })hase of Ihe subject has received considerable attention. It 

 has been our aim to determine the effect of repeated injections of vinis 

 blood and tail bleedings on the agglutinative power of the blood of 

 "serum hogs." 



We assume that the following factors influence the production of ag- 

 glutinins in the bodv fluids: 



