140 Concluding Remarhs 



its application to these new cercarioe the morphological clue fully vindi- 

 cated its use. Within three months no less than four B. cercaricB were 

 obtained by this method of exclusion. Two of these were selected, on 

 epidemiological and other grounds, and with these two alone experiments 

 were made on Cercocebus fiiliginosus and other animals. These forms 

 proved to be the infective stages of the two bilharzia worms which cause 

 bilharziosis in man in Egypt. No experiments were made with any other 

 cercariae. 



Here I may well bring to an end a Report that has been kept open much 

 longer than was intended, and of which the earlier sections were written 

 while experiments were yet in progress. Much material remains which, 

 when elucidated, should add further to our knowledge of these and allied 

 Egyptian parasites. Its description, however, scarcely comes within the 

 terms of the present inquiry, which were " to investigate bilharzia disease 

 in Egypt, and advise as to the preventive measures to be adopted in con- 

 nexion with the troops." These objectives, I believe, have been fully 

 achieved. A complete zoological study of the adult parasites, or of their 

 development, has not been attempted. Such attention as has been given 

 to their morphology and bionomics has been directed to those points con- 

 cerning which an understanding was essential as a basis for prophylactic 

 measures. The difficulties which beset the inception of the work in a 

 strange country, with some elements critical and hostile, were quickly over- 

 come. Sickness, however, almost wrecked the inquiry at its commence- 

 ment. Within a month of our arrival Dr. Cockin had fallen sick, and was 

 invalided home. Three weeks earlier I had been admitted to hospital with 

 scarlet fever. It was not until the beginning of April that, foregoing my 

 convalescence, I was able to start field investigations at Marg. Early in 

 May the opening of the Gallipoli campaign, with its rush of wounded and 

 the attendant excitement in Cairo, brought pressing local suggestions for 

 the foreclosing of my mission. As on some other occasions, one found 

 comfort in the aphorism of Huxley : " Surely there is a time to submit to 

 guidance, and a time to take one's own way at all hazards." 



But the pervading restlessness could not be wholly withstood. Later, in 

 June, when it seemed advisable to transfer the work to London, my second 

 colleague, whose assistance had been invaluable, decided to remain in Egypt 

 for general service with the Eoyal Army Medical Corps. The position of 

 the inquiry was full of anxious uncertainties, and I had still to complete 

 many of the crucial experiments. The collections made in the field had 

 still to be worked out, and the experimentally infected animals examined 

 histologically. The extensive literature of Bilharziosis had to be over- 

 hauled. Finally, new experiments had to be made. These were the 

 circumstances in which the preparation of the Report had to be undertaken, 

 and sole responsibility assumed for the conclusions arrived at and for the 

 views herein set forth. 



John Bale, Sons and Daniblsson, Ltd., 83-91, Great Titchfield Street, W. 1. 



