PIROPLASMA lUCE.MlNLM AND ANAPLASMA CKNTRALE. 35I 



Bull 4412. No reaction occurred to Reciwater. l)ut one did to 

 A. ccntralc from 41st to 50th day. 



Bull 4413. No reaction was noticed t>i redwater. Init a 

 reaction occurred to A. cciitmlc from 41 st to 49th day, when 

 death occurred from acute anaplasmosis. Only the centrale 

 form of. anaplasma could be found in blood smears during life 

 and in blood and spleen smears after death. No previcus case 

 of death from the centrale type of anaplasmosis has occurred 

 in the history of experiments in anaplasmosis since their com- 

 mencernent some years ago. In the cases of both bulls 4412 

 and 4413 the temperatures could not be taken jjroperly for the 

 same reason as in the case of bull 4410. 



The results of Experiment 6 were again disappointing and 

 inconclusive, owing chiefly to uncontrollable circumstances ; so 

 that it was decided to do further experiments on 19 recently 

 imported bulls, on which the owner was willing that experiments 

 should be carried out. 



ExPERi.MEXT 7. 



The experimental work was arranged as follows : — -Heifer 

 4120 (see Experiment I ), immune to redwater and anaplasmosis, 

 was bled into varying proportions of isotonic sodium citrate solu- 

 tion (3.8 per cent. ). to which Vs per cent, gelatine had been added 

 to prevent haemolysis. The addition of the gelatine was sug- 

 gested by an article written by Peyton Rous in the " Journal of 

 Experimental Medicine "' for February ist, 1916. Vol. 2;^, No. 2, 

 in which gelatine was successfully used in keeping suspensions of 

 red blood corpuscles from injury during washing. Blocd was 

 added to the citrate solution in the proportions of 90 to 10. 

 70 to 30, and 50 to 50. A control lot was made by adding 90 

 of blood to 10 of 10 per cent, citrate* solution, as used in some of 

 the other experiments, and a lot consisting of defibrinated blood 

 with no addition of preservative. Bottles of each of these five 

 batches were kept for periods of 48, 96, and 144 hours, respec- 

 tively, being sent by post to various places and returned. In 

 the bottles containing citrate solution, no haemolysis occurred until 

 the end of the second week in control ones sent out with those 

 which went on journeys, so that haemolysis could not be said to 

 have affected the experimental results. The defibrinated blood, 

 unpreserved, became infected with a coccus-like organism, so the 

 bottles of it over 48 hours old were not used. 



The bulls in the experiment were first of all inoculated 

 with the various citrate solutions, those which reacted to Ana- 

 plasma centrale only being subsequently inoculated with blood 

 of heifer 4390, which contained a virulent strain of P. higcm- 

 inum. Those which did not react to either P. bigctninum or 

 Anaplasnva centrale were reinoculated with blood of heifer 4120^ 

 the blood being inoculated directly after taking. These re- 

 inoculated cattle were subsequently inoculated with blood of 

 heifer 4390 (virulent Redwater strain). The results are shown 

 in the following table : — 



