20 



INTRODUCTION 



Private 

 Workers 



made of such facilities as the laboratories afford, not only in tiie directions mentioned, 

 Water-supply but iu liygieiiio work, more especially of course for Khartoum. Thus, a prolonged 

 investigation ou the proposed water-supply for this city taxed severely the resources 

 both of the chemical and the bacteriological departments and left but little spare time 

 for research. As will be seen, however, this water enquiry, which turned out to be one 

 of great interest and complexity, soon assumed the nature oi a research which led, 

 I believe, to the satisfactory solution of an important and ditlicult problem. 



These are but a few examples of the purposes which the laboratories iwv/ serve. 

 The scope of the work and details regarding it will be considered immediately, but here 

 one would chronicle a new development, namely the advent of private workers who, at 

 their own charges, have spent a considerable time in Khartoum carrying out research 

 work in the laboratories and, for the sake of gaining experience in tropical work, kindly 

 assisting the 8tafif iu routine and other work. Thus, during the winter 1908-9, 

 Dr. A. C. Stevenson of the University College Hospital, London, was one of these 

 volunteers and he rendered good service by discovering coccidiosis in Sudanese goats, 

 an observation which enabled the veterinary officers to take measures for stamping out 

 the disease amongst infected herds. Dr. Stevenson also investigated the hiematozoa and 

 intestinal protozoa of the common toad in Khartoum, and he contributes papers on both 

 these subjects to this Keport. He has also kindly supplied the drawings illustrating 

 them. Dr. W. M. Aders, our other free-lance, was here at the same time as 

 Dr. Stevenson. In addition to helping us with his zoological knowledge he studied the 

 subject of hyper-parasitism, and contributes a paper on his researches into the 

 Herpetomonas parasite which he found in AsjMnr/ojnis vidiiatus, the melon bug of 

 the Sudan. 



Since these gentlemen left, applications have been received from an Italian Scientist, 

 an American Professor and a medical missionary resident in Persia, Ibr permission to 

 study tropical medicine in the laboratories. Unfortunately, we have little spare room at 

 our disposal, but in one of these cases arrangements have been made to grant the 

 request, and Professor E. F. McCampbell of the Ohio State University, Columbus, will, 

 I hope, be our guest and fellow-worker during the winter of 1911—2, both in the main 

 laboratories and in the floating laboratory. The latter has been most usefully employed 

 in the service of the Kala-azar Commission on the Blue Nile, and reports of the work 

 done will be found included. The subject of transmission ia this disease is a very 

 difficult one, but Lieut. W. E. Marshall's careful observations go some way towards 

 solving the problem. 



Before proceeding briefly to outline the work ucuuinplinhcil in the different sections, 

 one has to record the fact that, at ^Ir. Wellcome's request, the distinguishing word 

 " Tropical " has been added to the title of the laboratories, and they will hereafter be known 

 as the Wellcome Tropical Kesearch Laboratories. As mentioned, the laboratory work has 

 Laboratories SO greatly increased, and the number of our outside contributors is on this occasion so 

 numerous, that it has been found advisable to split the Fourth Keport into two volumes, 

 the first dealmg with medical, the latter wth general science. At the time of writing, 

 it is also hoped to bring out a Second Review Supplement more or less on the same lines 

 as that issued as an appendix to our Third Report. We have received a good many letters 

 testifying to the utility of that publication and expressing a hope that another volume 

 would be forthcoming. Hence, both for our own sakes and for workers in the Sudan and 



