2 THE AMOEBAE LIVING IN MAN 



The War unexpectedly gave me an opportunity of studying, on 

 a large scale, all the intestinal protozoa of man. In 1915 large bodies 

 of troops from the Eastern War Areas began to arrive in this country. 

 It was at first believed that amoebic dysentery had been responsible for 

 a very large proportion of the invalidism in our troops from Gallipoli 

 and Egypt : and although we now know that this was a mistake, it 

 called for protozoological examination of the stools of a very large 

 number of military patients invalided home with a diagnosis of " dysen- 

 tery." No machinery for coping with such diagnostic work on a large 

 scale existed at the time, and it thus became necessary to train and 

 organize a number of workers specially for the purpose. This work was 

 begun by Dr. C. M. Wenyon, who was at that time most qualified to 

 undertake such a difficult task ; but after he had made a beginning, his 

 services were demanded elsewhere, and at the request of the Medical 

 Research Committee I took charge of the work at the end of 1915.* 

 Since that time I have, with the permission and assistance of the 

 Imperial College, devoted myself uninterruptedly to the practical study 

 of the intestinal protozoa of man. A large part of my time has, of 

 necessity, been occupied with routine work of diagnosis, with teaching, 

 and with the investigation of methods of treating amoebic dysentery. 

 But nevertheless I have had, during the whole of this period, great 

 opportunities for studying the human intestinal protozoa from the 

 zoological standpoint. I believe, indeed, that no zoologist has ever 

 before had such an immense amount of material at his disposal for 

 a study of the intestinal amoebae of man. 



During the War I have naturally followed, with the keenest interest, 

 all the work which has been done upon the present subject — so far as 

 the results of other workers, both at home and abroad, have been 

 ascertainable. I have also recently read, or re-read, most of the pre- 

 viously published work, in order to correct my earlier impressions and 

 clear up my former difficulties in the interpretation of the results of 

 many other workers. In the light of present knowledge, and with a 

 large personal experience to fall back upon, I now find but little diffi- 

 culty in understanding many observations which formerly puzzled me : 

 and so far as the intestinal amoebae of man are concerned, I believe 

 that it is now possible to claim that all the chief problems of the past 

 have been solved. For my own part, at all events, I can now say that 

 almost all my own doubts and difficulties have disappeared. 



Having thus reached definite conclusions on many points, and 

 having corrected or verified many of the observations of others, so that 

 their findings are reconcilable with my own, I have thought it a not 

 altogether thankless task to record the main results. I have endeavoured, 

 in the following pages, to deal fairly with the work of all my prede- 

 cessors ; and I have done my best to cope with the immense and 

 scattered literature on amoebae and amoebiasis. I hope I have not 

 omitted to study any previous work of material importance from the 

 zoological standpoint. If so, it is through ignorance of its existence, or 

 ifiability to gain access to it. On the other hand, I have knowingly 

 Ignored much purely medical work ; and for the reason that it is not 



* A full account of the circumstances here briefly alluded to will be found in the 

 Introduction to Special Report No. 4 (1917), published by the Medical Research 

 Committee. 



