114 Lately Captain R. J. C. Thompson, R.A.M.C, who has done such good work in charge of the sleeping sickness camp and in connection with clearance operations, sent me the blood of three of the transport bulls working on the old Belgian automobile road which runs from Rejaf on the Nile, through Loka and Yei, to Aba on the Congo frontier.

He had found these animals infected, and was anxious to know the type of trypanosome present. We will, therefore, first consider the infection in the case of these bulls. A mere glance at the films showed that we were dealing with a trypanosome of the pecoruninamim-congolense group. The films had been fixed in absolute alcohol, and, though rather old, stained sufficiently well with Giemsa to permit of their being accurately drawn at a magnification of 2,000 diameters by the aid of Greil's projection apparatus. This, combined with Bruce's method of measuring, is probably the most accurate means of determining the dimensions of stained trypanosomes. The best results are, however, obtained by fixation with osmic acid. From the three slides 140 parasites were drawn and measured. Attached is the curve (Chart I) obtained on plotting the measurements according to Bruce. It will be found to answer very closely to that for the Sudan T . nannm, shown in Vol. A of the Fourth Report of these Laboratories (1911, p. 55). The trypanosome is small, short, and shows no free flagellum. The following statement gives the figures in respect to length : 4 Minimum Maximum Average Length in microns ... 98 ... 17 ... 126 These dimensions are quite near enough those given by Bruce, Laveran and Mesnil and other observers for T . naniim to permit of its being considered as this trypanosome, so far as length goes. The breadth at the broadest part varied from i// to 2/u, which is also in keeping with that of T. nanum. The accompanying microphotographs show sufficiently well the general aspect of the parasite, PI. IX, fig. i shows a typical short T . nanum-Uke form ; fig. 2 a longer variety with a better marked undulating membrane. Neither shows any free flagellum. The infection was, in none of the three cases, very heavy, but I am informed it is proving fatal to the transport bulls. Captain Thompson also informed me that he thinks it may be associated with trypanosomiasis in a herd of cattle