246 
Annals of the Transvaal Museum. 
The transmission of the disease with blood has hitherto not been 
successful, and this may be explained by the fact that the gametocytes 
do not develop any further, and do not undergo parthenogenesis. If it 
is possible to transmit the disease with blood, such can certainly only be 
the case at the beginning before gamogonous forms appear. In the trans- 
mission experiments with organs, as undertaken at the Laboratory, 
agamonts are inoculated, that is, forms which are capable of further 
development. 
The parasite in the red corpuscle can only undergo further develop- 
ment after it has entered into the tick. The gametocytes contained in the 
blood then develop further. When copulation occurs in the tick, micro- 
and macrogametocytes can be distinguished in the blood. The gameto- 
cyte, which is ring-shaped or pear-shaped, takes either on the elongated 
or so-called bacillary form, or it grows into a broad ring or becomes more 
pear-shaped. The former represents the microgametocytes, the latter 
the macrogametocytes. (Figures 16 and 17.) 
After the infected blood corpuscles have reached the stomach of the 
tick, the parasites emigrate within the first half-hour. A great number 
perish. Only the mature gametocytes grow into gametes and mix with 
each other. The microgametes contain a distinct small nucleus similar 
to the centrosome or blepharoplast (Browazek and Hartman) of other 
organisms, which acts as the initial agency for the development. 
The fertilized macrogamete (figure 18) “ rounds off ” after a kary- 
myoxis and from this the ookinete results and similar to other blood 
parasites takes the shape of a retort changing into that of a gregarine, 
and finally grows into the elongated ookinete. The ookinetes can be 
recognized by their activity — they double back and stretch out rapidly, 
and show contractile movements like gregarines. 
The forms given in figures 19-22, I have as yet found only in infected 
ticks on the eve of moulting. During the moulting process, I was unable 
to trace any intermediate forms which would lead from the ookinetes to 
the agametes of the first generation (sporozoites) as shown in figure 1. 
With the formation of the agametes the evolution of Theileria parva is com- 
plete, and when these agametes find their way into a beast the described 
cycle commences afresh. 
Decently some publications have been made by Nuttall, Fantham, 
and Porter on Theileria parva , in which the evolution cycle of the East 
Coast fever parasite has been studied in stained dry preparations. Since 
these investigators did not mention in any way the evolution forms in 
the organs, and their investigations have not come to a conclusion except 
in regard to the already known facts, such as number and shape of the 
blood parasites, I cannot enter into any discussion for the time being. 
I only wish to repeat that my observations have been made on living 
material, and with preparations fixed by moist methods, and I wish to 
draw attention to the detailed illustrated report due to appear shortly 
in the “ Archiv. fur Protistenkunde ”, and in the report of the Government 
Veterinary Bacteriologist of the Transvaal, in which I have particularly 
referred to literature on the subject. 
