110 Journal of the Department of Agriculture. — Aug., 1922. 



(2) Further inland, varying from twenty to thirty miles from 

 the coast, the veld is less sandy, consists in fact, in some places of 

 alluvial soil washed down from the Lebombo Mountains. The veg"e- 

 tation here is of quite a different nature to that described in the 

 previous paragraph, for instead of a minimum of shade, one sees 

 bushveld varying from scrub with numerous glades to thickets or 

 even vast areas of dense bush, e.g. Ipapa Bush in an angle formed 

 by confluence of Usutu and Pongolo llivers. I may mention that 

 fossils collected by me in this area have ueen identified as being of 

 marine origin by the Director of the Geological Survey. In this type 

 of country, i.e. bushveld, Nagana is the disease most frequently 

 encountered, being enzootic in the areas where tsetse flies are found, 

 and epizootic , around the enzootic areas. This state of affairs was 

 noted not only in the Lower Umfolosi District, but also throughout 

 the country. In enzootic centres, it would seem that wild mammals 

 act as reservoirs and that tsetse flies are the chief transmitting agents. 

 but in epizootic areas, domesticated animals take the place of wild 

 mammals and biting flies, other than tsetse, are responsible for pro- 

 pagation of the disease. From observations made at Ntambanana, it 

 would appear that there is good reason to incriminate species of 

 Haeviatojjota, Pangonia, and Tahanvs. And »3) it also seemed clear 

 (there are a few exceptions) that natural transmission coald not take 

 place on high veld, by which I mean elevations exceeding 1500 feet. 

 As high veld is open grass veld, the importance of shade as a factor 

 in natural transmission is obvious. 



Erecting the Laboratory and Other Buildings. — September, 

 1921 — December, 1921. — As the building material had now arrived, 

 active progress was made in construction of laboratory, store rooms, 

 sheds, and quarters for staff. Apart from three native handymen sent 

 down from Onderstepoort, all buildings were erected by my lay assist- 

 ant and stockman, to whose energy and untiring efforts, I am much 

 indebted. The fencing of the station was also taken in hand, and 

 water -boi'ing operations carried out, the latter, unfortunately, with 

 no success. During this period, routine work such as the examina- 

 tion of blood slides was commenced, and after Ihe inspection of some 

 hundreds of smears, it was recognized that the inost frequent cause of 

 Nagana was a small trypanosome known as Trypanosoma congolcnse, 

 and that Trypanosoma briicei, hitherto considered to be the cause of 

 Nagana in Zululand, was present on only rare occasions. 



Tartar Emetic Treatment. — January, 1922 — April, 1922. Ai^ 



facilities now existed for the proper carrying out of investigation 

 work, efforts were made to obtain some agent that would prove useful 

 in cases where Nagana infection had taken place. It was realized that 

 a specific was not available, and all that could be hoped for was some 

 form of palliative treatment. After preliminary tests, it was decided 

 to carry out on a large scale under field conditions, the tartar enieiic 

 treatment used in Portugiiese East Africa by Jones in 1912, and later 

 adopted by Hornby in North-East Rhodesia the following year. My 

 policy has been to impress upon all farmers the importance of early 

 diagnosis. If blood smears are negative, and yet the first manifesta- 

 tions of Nagana are observed, then no time should be lost in com- 

 mencing treatment with tartar emetic. 



