VETEKINAKY SCIENCE AND PEACTICE. 187 



were each inoculated with 2^ cc. of blood from a recently immunized 

 animal, with entirely satisfactory results. Mr. J. T. Bryant success- 

 fully inmuinized '2 Hereford j-earlings (imported from Iowa) by inocula- 

 tion with 2 cc. of blood from a native yearling. 



The authors give a description of the method to be used in securing 

 the blood for inoculation and in making the inoculation in animals to 

 be immunized. Experiments were conducted for the purpose of deter- 

 mining whether the blood in ticks could be used for inoculation pur- 

 poses. Ticks were collected and carefully washed in a solution of 

 corrosive sublimate and sterilized water. The blood from these ticks 

 was then used in inoculating 4 animals. The first animal (a grade 

 Shorthorn) was inoculated with blood obtained from 3 large cattle ticks 

 which had been removed from native cattle. The temperature of this 

 animal showed an elevation one week after the injection, then returned 

 to the normal, and became high again 15 days after the injection. The 

 highest recorded temperature was 104.6^ and the blood corpuscles 

 were diminished by about one-third. The animal was placed on a tick- 

 infested pasture in the following spring without showing any evidence 

 of fever. The second animal (a grade Shorthorn) was inoculated on 

 August 29. Its temperature was quite high during the 2 following 

 days, but returned to the normal on the fourth day. Since it seemed 

 doubtful whether the animal had really become immune, a further 

 inoculation was made with blood taken from ticks which had been main- 

 tained for 7 hours at a temperature of — 12° C. After this second 

 inoculation, the number of blood corpuscles diminished, but there was 

 no temperature reaction except for one day. Later, a single tick was 

 found on the animal, so that this case was considered too complicated 

 for drawing definite conclusions. The third animal was a common 

 2-year-old steer which was inoculated with blood from ticks which had 

 been kept for 7 hours at a temperature ranging from — 10 to — 12° C. 

 The animal developed no symptoms of Texas fever for 18 days after 

 the inoculation, and was then inoculated with blood from a native 

 cow. One week later a good case of inoculation fever developed. It 

 appears from this experiment that the organism of Texas fever ma}^ be 

 destroyed or attenuated while in the body of the ticks, and this ma}' be 

 the explanation of the fact that tick infestation in late fall or early 

 spring produces a milder form of the disease than that of midsummer. 

 The fourth case was a heifer which was inoculated with the blood from 

 ticks and developed a high fever on the nineteenth day after inocula- 

 tion, the blood corpuscles being also reduced by about 50 per cent. 

 Recovery then began to take place, but the animal became deeply mired 

 during this time and died. 



An experiment was tried in the preservation of blood for inocula- 

 tion purposes. One-tenth per cent of potassium oxalate was added to 

 blood and this blood was then sent to Ann Arbor and tried at home 



