112 



Dr. A. Theiler. Transmission of Amakebe [Apr. 20, 



dioxide and water). The difficulty, however, is imaginary, and the result is possible, because 

 (a) the position of equilibrium in the reversible change C0 2 + 3H„O^HCHO + 2H s 2 is 

 displaced towards the right by the addition of light energy, and (b) the process is 

 continuous so long as the products on the right-hand side are removed, as in a living plant 

 they are. 



H. Euler (' Zeits. fur physiol. Chemie,' 1909, vol. 59, p. 122) supports Ewart's criticisms, 

 without, however, giving any particulars (cf. foregoing paragraph). He also mentions 

 some experiments with solutions of chlorophyll, quinine sulphate, and fluorescein, which 

 gave negative results. This agrees with our own experience, so far, at least, as chlorophyll 

 solutions are concerned. 



Mameli and Pollacci (' Atti dell' 1st. Bot. dell 3 Univ. di Pavia,' Series II, vol. 13) have 

 published a critical memoir in which, in the first place, they re-affirm the possibility of 

 detecting formaldehyde in the living plant : this appears now to be fully confirmed by 

 Schryver (loc. cit.). These authors also failed to observe any evolution of oxygen in vitro 

 when they repeated the experiment already referred to, but it is possible that, as they 

 stated that they were unable to prepare a specimen of chlorophyll free from formalde- 

 hyde, this substance may have interfered with the action of the catalase in contact with 

 the film of chlorophyll, in which case no oxygen would be produced. 



Transmission of Amakebe by means of Rhipicephalus 

 appendiculatus, the Brown Tick. 



By Dr. A. Theiler, C.M.G., Pretoria. 



(Communicated by Colonel Sir D. Bruce, C.B., F.E.S. Received April 20, — Read 

 May 18, 1911.) 



That the disease in calves of Uganda called Amakebe is identical with 

 East Coast fever had to be concluded after the presence of the so-called blue 

 bodies of Koch, or plasma bodies, had been demonstrated in the internal 

 organs ; these bodies represent certain stages, agametes, agamonts, and gamonts, 

 in the life cycle of Theileria parva. Accordingly, it had to be expected that 

 Amakebe could be transmitted by means of such ticks, which act as hosts 

 for this parasite. The most common tick of Uganda is the Brown Tick 

 Rhipicephalus appendiculatus, which has been proved in South Africa to be 

 the principal transmitter of East Coast fever. 



When in Uganda in 1909 an arrangement was made between Mr. Hutchins, 

 the Government Veterinary Surgeon of Uganda, and myself, to place adult 

 brown ticks, collected as nymphse from calves suffering from Amakebe, 

 on susceptible calves in my laboratory in Onderstepoort, Pretoria, Transvaal ; 

 these ticks were to be collected by Mr. Hutchins as opportunity occurred. 



