NA JURE 



369 



THURSDAY, DKCKMBER 11, 1919. 



PARASITIC AMOiB.E AND DISEASE. 



The Amoebae Living in Man: A Zoological Mono- 

 graph. By Prof. Ciiflord Dobell. Pp. vii + 

 15.STV plates. (London: John Bale, Sons, 

 and Daniel^son, Ltd., 1919.) Price js. 6d. 

 net. 



""PHIS is a very valuable piece of work, bringing 

 -L order and critical intelligence to bear in a 

 field of study which, already touched by many 

 observers, has immensely increased in activity and 

 importance during the war. The common fresh- 

 water .\mctba, living freely in natural pools, has 

 many relatives, some of which have been distin- 

 guished by definite characters of the nucleus, form 

 of pseudopodia, cysts, and other characteristics 

 as "good " species and even assigned to distinct 

 genera. I3ut there has been no careful cytological 

 study of the various species, though here and there 

 important observations have been made. When 

 to these forms are added those living in the soil, 

 in sea-water, and, lastly, those parasitic in other 

 animals, we find that there is quite a large group 

 of these "amoeboid " organisms which have been 

 recorded from this or that habitat by observers 

 who were hurried by other work or insufficiently 

 trained in cytological methods. As a consequence, 

 without sound method or criticism, specific and 

 even generic names have been gi\en to "Ama^b;c," 

 parasitic or free-living, and misleading sketches 

 of them have been published. A perplexing con- 

 fusion of inaccurate statements obscures the whole 

 subject. 



A great source of inaccuracy and vague state- 

 ment has been the interest excited among medical 

 men by the parasitic species of Amcrba-like organ- 

 isms and their association with dysentery and pos- 

 sibly with other diseases. As a rule the medical 

 observers have not been trained " protozoologists," 

 or attentive to the laws of zoological nomencla- 

 ture. It is creditable to them that in the midst of 

 other important work they have done so much in 

 directing attention to these parasites. But to give 

 any serious value to a knowledge of the Amteba? 

 as a guide to the diagnosis and control of disease, 

 it was absolutely necessary that a high standard of 

 accuracy in observation and statement, correct 

 nomenclature, and a severe criticism of the accu- 

 mulated mass of loose statements published by 

 incompetent though well-meaning writers, should 

 be applied to this subject by a competent 

 auth(3rity having not only special experience 

 and understanding of systematic zoology, 

 but also time and opportunity to ensure full 

 examination by him of the organisms in 

 question. 



The (iovernment was fortunate in being able to 

 secure the services of Mr. Clifford Dobell, assis- 

 tant professor of Protistology and Cytology in 

 the Imperial College of Science, for this purpose. 



NO. 2615, VOL. 104] 



Prof. Dobell had before the war made for himself 

 a distirkguished name as an investigator of the 

 structure and reproduction of such minute para- 

 sites as the Coccidia, the Bacteria, and, amongst 

 others, of the .\mnebae parasitic in frogs. He had 

 carried the discrimination of details in the struc- 

 ture and reproductive changes of the threads and 

 granules of the cell-nucleus of such minute 

 organisms beyond that attained by other micro- 

 scopists. His careful and precise work was recog- 

 nised by his scientific confreres as certain to lead 

 to sound conclusions when applied with ample 

 time and material to the problem of the relation 

 of Amcebae to disease in "man, and especially to 

 the question of the causation of dysentery (and 

 other disea.ses) by one, or more than one, species 

 of .Vmceba. 



In 1915 the return to this country of large bodies 

 of troops from the Eastern war area — manv 

 afflicted with dysentery — rendered it necessary to 

 examine the stools of a very large number of 

 patients in order to decide whether those returning 

 from (iallipoli and Egypt were suffering, as was 

 supposed (but shown to be erroneously so), from 

 "amoebic dysentery." A large number of trained 

 workers were required for this purpose. Their 

 training was undertaken, at first, by Dr. C. M. 

 W'enyon, but when his services were required else- 

 where at the end of 1915, Prof. Dobell took charge 

 of the work and for four years has devoted himself 

 uninterruptedly to the practical study of the in- 

 testinal protozoa of man. A large part of his time 

 has been occupied with the routine work of diag- 

 nosis, with teaching that routine to others, and 

 with the investigation of methods of treating 

 amcebic dysentery. But, as he says, he has had 

 great opportunities for studying the human intes- 

 tinal protozoa from the zoological point of view, 

 and probably no zoologist has ever before had 

 such an immense amount of this special material 

 at his disposal. 



.'Vs a result, in spite of the really formidable 

 difficulties in interpreting ihe results of many 

 other workers. Prof. Dobell is able to say that 

 almost all his own doubts have disappeared, 

 and he presents to other workers in this field 

 in the present volume a very full and detailed 

 account of the work of his predecessors and of 

 his own work and conclusions — together with 

 the story of his methods of microscopic observa- 

 tion-illustrated bv five remarkably well-executed 

 plates. 



This book is not for the general reader, and not 

 even for every zoologist. It is addressed to the 

 protozoologist who has some familiarity with the 

 later developments of cytology, and is either 

 already engaged in such studies or qualifying for 

 them. At the same time we mav briefly direct 

 attention to some of Prof, nobcll's conclusions 

 ■'vhich have general interest. For reasons fully set 

 forth, he reduces the number of species of 

 " Amteba; " ascertained to be living in man to 

 six, which he arranges in four genera, as 

 follow.s : — 



