264 



Col. Sir D. Bruce and others. 



[Dec. 18, 



Bemarh.—Six days after the injection of blood containing the Piroplasma bigeminum, 

 this parasite appeared in the blood. The temperature curve is not aftected, nor does the 

 calf appear ill. It may, therefore, be concluded that Amakebe is not caused by the 

 injection of blood containing either Piroplasma higemimim or the small rod and ring 

 form. 



It is well known that Piroplasma higeminum is carried from affected to 

 susceptible animals by different varieties of the blue tick, as well as other 

 species of ticks. It would seem that the small rod and ring form of piroplasm 

 is carried by the brown tick, as the following two experiments will show. 



Experiment 7-17. 



To ascertain if Brown Nymphs which had fed as larvie on an Animal whose blood 

 contained the Small Rod and Ring Forms, are capable of carrying them to a 

 Susceptible Animal, and if the disease so set up will have the Symptoms of 

 Amakebe. 



.Tune 24, 1909. — This calf, like the others, has been brought up in a tick-fi'ee shed. It 

 has been under observation since May 10 without showing any small rod and 

 ring forms in its blood. To-day, a large number of brown nymphs which 

 had fed as larva; on an ox whose blood contained the small rod and ring 

 piroplasm were placed on this calf. 



The following chart shows tlie course of the temperature : — 



Jkte 



June 1309 Julv 















X 



/ 



z 







5 



6 



7 



8 



9 



io\/i 



IZ 





H 



15 



i6\n 



IS 



ij 



104° 























































103° 













































d 











102° 







f 





/ 





t 



t 





t 



\ 



/ 













\ 



p 



k 



/' 









■ — 



f 



































t 











ioo° 























































pirqp. 





















































+ 



Chart 8. — Kxperiment 747 represents the Temperature Curve of a Calf upon which 

 Infected Brown Nymphs have been fed. The mhmit and pins signs show the 

 absence or presence of the small rod and ring ])iroplasm in the blood. 



I'evHirks. — Twenty-five days after tlu; infected lirown nymphs were fed on this calf the 

 small rod and ring-shaped ])iroplasm ajjpeared in the blood. Tlie leniperatui e curve is 

 not affected, and the calf shows no signs of Amakebe. It is evident, then, that the small 

 rod and ring-shaped piroplasms transferred to a susceptible calf by means of brown 

 nympiis do not give rise to amakebe. 



Experiment (i.^D. 



To ascertain if Adult BrowTi Ticks wliicli had Eed as Nymphs on an Animal whose Blood 

 contained the Sniiili i'nd and King Forms are eai)ablo of carrying them to a 

 Susceptible Animal and setting \\\) the Symptoms of Amakebe. 



Aug. 23, 1909. — This calf was boiii on April 4 in a tick-free shed. It has been examined 

 almost daily since that date, and up to the present has sliown no parasites of 

 any kind in its 1)1()0(1. To-day, a liirge number of adult brown ticks were 

 placed on this calf. 



