422 



NATURE 



[August i, 191 8 



producing- permaneat stiffness, even in a healthy 

 joint, by immobilising a limb. Indeed, Prof. 

 Broca shares this fear to some degree, and re- 

 commends that complete immobilisation of limbs 

 should be practised only during transport of the 

 wounded. 



For the recovery of stiffened joints voluntary 

 movements are recommended in preference to 

 passive movements. Indeed, Prof. Broca is of 

 opinion that in many slig-ht cases of stiffness of 

 joints a ten hours' day at manual labour is the 

 very best treatfnent possible, so long as such 

 exercise is not attended by positive pain. We 

 note, too, that the author, in his introduction, 

 gives the following quotation from Ecclesiastes 

 as being- true of orthopaedic practice in France : 

 " There is no remembrance of former things ; 

 neither shall there be any remembrance of thing's 

 that are to come with those that shall come after." 

 We in England are making similar discoveries ; we 

 find that many of our discoveries are really re- 

 discoveries. 



THE PARASITIC HYPOTHESIS OF 



TUMOURS. 



Tumours: Their Nature and Causation. By Dr. 



W. D'Este Emery. Pp. xx+146. (London: 



H. K, Lewis and Co., Ltd., 1918.) Price 55. 



net. 

 T^R. EMERY'S book is remarkable in two ways. 

 ■■--' In the first place, it is a' clear and concise 

 statement of the parasitic hypothesis of the causa- 

 tion of new growths — a welcome innovation in a 

 subject around which more dubious writing has 

 been perpetrated than any other in medicine. In 

 the second, it does not contain any original ob- 

 servations. After summarising and discarding 

 the current definitions of "tumour," the author 

 sets up three postulates to which the required 

 parasite should conform— viz. ultramicroscopic 

 size, intracellular or intranuclear habitat, and pro- , 

 duction of a toxin capable of stimulating growth 

 in the invaded cells. The remainder of the work 

 is devoted to a rapid review of the more prominent 

 features of tumours, showing how they fit in with 

 these assumptions. Benign growths are those with 

 few parasites in each cell, giving weak action of 

 the toxin; in malignant growths the cells are 

 heavily loaded, much toxin is produced, and 

 growth is energetically stimulated. At once we 

 come in contact with the subsidiary assumption that 

 the cells of the body grow only when stimulated. 

 It is at 'least arguable and probably true that, on 

 the contrary, growth goes on so long as life lasts. 

 The contrast to the form of growth presented by 

 the limited reactions to known toxins is got over 

 by assuming a nicely balanced symbiosis of host- 

 cell and parasite, the parasite not getting out of 

 bounds and killing the cell, and the cell not being 

 sufficiently irritated to kill the parasite. 



Sarcoma development in the stroma of carcino- 

 mata (spontaneous or propagated) is regarded as 

 a transference of the virus from the carcinoma 

 cells to the connective tissue cells. The stroma of 

 tumours is not, as the author says, merely granu- 

 NO. 2544, VOL. lOl] 



lation tissue, unless we admit also that the stroma 

 of the*pancreas, the liver, the lung, and the kid- 

 ney is also granulation tissue. Although deriv6^d 

 from the homogeneous, ubiquitous mesenchyme of 

 the embryo, each of these organs has a character- 

 istic stroma, and the same has been demonstrated 

 for quite a number of carcinomata of the mouse 

 and rat. In both cases they appear to be specific 

 reactions of a single tissue to different paren- 

 chymata. The peculiarities of the process of sar- 

 coma development, the long contact which is 

 necessary, and the ultimate loss of the property 

 are not touched upon. Perhaps they would involve 

 too many and too intricate subsidiary assumptions. 



The chapter dealing with the evidence from the 

 organ-incidence of cancer shows the weakest side 

 of the hypothesis. If we restrict our survey to 

 cancer in man, as Dr. Emery does, the distribu- 

 tion appears rational, but it is otherwise when the 

 tumours of animals are taken into account. 

 Cancer of the mamma and of the uterus are com- 

 mon in man; cancer of the mamma is nearly as 

 common in mice, but carcinoma uteri is very rare. 

 Cancer of the stomach also is rare in mice, but 

 common in the cow, while in this animal cancer of 

 the mamma and of the uterus are both rare. Can- 

 cer of the liver is the commonest new growth in 

 the cow and other herbivora. Next in frequency 

 are new growth of the adrenal and carcinoma of 

 the stomach. In the horse carcinoma of the liver is 

 rare, while growths of the adrenal are common. 

 The mouse and rat are closely related animals in 

 structure, habits, and diet. Their new growths 

 have a totally distinct organ and tissue incidence. 

 To harmonise these well-known facts of the natu- 

 ral history of cancer with the hypothesis would 

 require, not three fundamental assumptions, but 

 nearer three hundred. 



To be of value a hypothesis must fulfil two 

 conditions. It must embrace without violence the 

 facts of the subject and require a minimum of sub- 

 sidiary assumptions. It must stimulate inquiry and 

 lead to the extension of knowledge. Whatever 

 shortcomings Dr. Emery's essay may have in the 

 first direction are made up for in the second. It 

 is safe to say that there is scarcely an assumption 

 made of which it is only necessary to ask oneself, 

 "Is this true, and how would you prove it?" to 

 provide a subject for an interesting inquiry. Dr. 

 Emery has rendered a great service to those en- 

 gaged in the study of cancer. He has put into 

 succinct and intelligible form the vague general 

 impression which hitherto has hovered around 

 the subject under the name of the parasitic 

 hypothesis. J. A. Murray. 



THE WAR AND THE BAGDAD RAILWAY. 

 The War and the Bagdad Railway. The Story of 



Asia Minor and its Relation to the Present 



Conflict. By Prof. Morris Jastrow, jun. Pp. 



160+ I map. (Philadelphia and London : J. B. 



Lipplncott Co., 1917.) Price 6s. net. 

 "pVpRYONE has heard of the Bagdad Rail- 

 -*--' way, and that its project for capturing 

 the trade of the East was one of the chief 



