NATURE 



505 



THURSDAY, MARCH 31, 1892. 



A ZOOLOGIST ON DISEASE. 

 Lecons siir la Pathologie compari'e de f Inflammation 

 faites a Flnstilut Pasteur en Avril et Mai, 189 1. Par 

 Elie Metschnikoff, Chef du Service k I'lnstitiit Pas- 

 teur. (Paris : G. Masson, 1892.) 

 "pjR. METSCHNIKOFF has in this volume given a 

 ^^ clear account of the general basis of his phagocyte 

 theory, tracing the significance of amoeboid cells or 

 phagocytes from the Protozoa upwards through various 

 groups of animals to the higher Vertebrates. He adduces 

 a vast number of facts, many of them new and now for 

 the first time published (with many beautiful coloured 

 figures), others cited from his own earlier publications 

 and from the work of cotemporary observers, to show 

 that inflammation is essentially a reaction of the phago- 

 cytes contained in animal bodies to the presence of 

 injured tissue or intrusive particles— a reaction which 

 consists in active movement to the injured spot on the 

 part of the phagocytes, and the ingulfing and digestion 

 by them of the offending matters. 



This volume appears opportunely. It will, I venture to 

 predict, be regarded as epoch-making, establishing on a 

 solid basis the theory of phagocytes, first sketched by 

 Metschnikoff about ten years ago,' and repeatedly 

 confirmed and elaborated by his brilliant researches. 

 It will enable the biological world to appreciate the 

 theory at its true value as one of the great generaliza- 

 tions of biology, worthy to take rank, after Darwin's 

 theory of natural selection, with Virchow's cellular 

 pathology, and Pasteur's doctrine of the Bacterial origin 

 of fermentations and infective diseases. 



It is worth noting (and weighing well the lesson con- 

 veyed) that the flood of light which the phagocyte 

 doctrine throws upon the nature and processes of 

 disease is not due to a medical man, nor even to one 

 of those industrious observers of the physical properties 

 of the tissues of the frog and the rabbit, who pursue 

 their researches by the aid of delicate recording drums, 

 balances, and pendulums, and have for some unexplained 

 reason at the present day been granted the monopoly of 

 the ancient and comprehensive title " physiologist." 



Just as the penetrating theories of Pasteur, the chemist, 

 on infective disease, were opposed by the medical pro- 

 fession, who regarded a chemist as an intruder in their 

 domain, so the medical pathologists and the more narrow- 

 minded devotees of the kymographion have, to a large 

 extent, opposed, rejected, and attempted to ridicule, 

 Metschnikoff's doctrine of phagocytes. Unfortunately, 

 medical education is too little based on thorough biologi- 

 cal training, and in this country the so-called " physiologist," 

 so far from being a naturalist, plunges into the diffi- 

 cult and not very fruitful task of applying the delicate 

 apparatus of the experimental physicist to the measure- 

 ment of processes occurring in the higher Vertebrata, 



' Mctschnikoffs comprehensive view of the significance of phaeocytes 

 was first made known to English readers by translations of two of his earlier 

 papers, almost immediately after their original publication, in the Quarterly 

 Journal of M,croscop,cal Science, .884. Ihey were entitled " Researches 

 on the I ntra-cellular Digestion of Invertebrates," and "The Ancestral 

 History of Inflammation. 



NO. I 170, VOL. 45] 



without ever attempting to gain a competent knowledge 

 of the ultimate structure and vital processes of the series 

 of lower animals. Had our physiologists and patho- 

 logists the advantage of even a moderate instruction in 

 zoology, comparative anatomy, and embryology, they 

 would be making progress towards dealing with many of 

 the problems the solution of which they in vain seek to 

 wring from the unfortunate frog and rabbit. Certainly, 

 it is not possible for a physiologist or pathologist with 

 any pretensions to an adequate knowledge of the structure 

 and activities of the organs and tissues of lower as 

 well as higher animals to fail to see the great value of the 

 generalization which brings together under a common 

 term the phenomena of intra-cellular digestion, of em- 

 bryonic cell-layers, of inflammation, and of immunity to 

 bacterial disease — which " explains " at once the mesoblast 

 of the Echinoderm-larva and the very existence of the 

 colourless corpuscles of vertebrate blood. The man who 

 sneers at " Metschnikoffism,"— that is, the explanation of 

 the phenomena of inflammation and infective diseases in 

 Vertebrate animals by a comparative study of these 

 phenomena in Protozoa, Sponges, Jelly-fish, Worms, 

 Crustaceans, and Mollusks— must be held to be either 

 very ignorant or morbidly prejudiced against zoological 

 studies. 



Elias Metschnikoff has been known for more than five- 

 and-twenty years as the most productive and accurate 

 investigator of the embryology of marine Invertebrata, 

 such as the Sponges, Medusae, Echinoderms, and Worms. 

 The amount and value of his researches in this field had 

 placed him by general consent in the very first rank, by 

 the side of his distinguished fellow-countryman Kowal- 

 ewsky, when, ten years ago, he was led to direct his 

 attention more especially to the study of the activity of 

 the amcEboid corpuscles of the blood and tissues of 

 certain transparent organisms in resisting infection by 

 vegetable parasites ; and thence to other questions of a 

 similar nature. Lately he has retired from the Professor- 

 ship of Zoology which he held at Odessa, and. accepted 

 a position giving him the control of an admirable labora- 

 tory in the Institut Pasteur in Paris. 



Metschnikoff commences his book with the statement : 

 " It is solely in my quality of zoologist that I have decided 

 to deliver these lectures on a subject which belongs to 

 the domain of pathology." Just as formerly, in com- 

 parative anatomy, account was taken only of Man and 

 the Vertebrata, so now, our author says, in medicine up 

 to the present time, all the pathological processes which 

 go on in the lower animals have been left out of con- 

 sideration. And yet the study of these lower animals, 

 which present simpler and more primitive conditions than 

 do Man and the Vertebrates, is capable of furnishing us 

 with the key, as it were, of those complicated pathological 

 phenomena which are most interesting for medical science. 

 Disease and pathological processes have— he reminds us 

 —their evolution, just as Mar. and the Vertebrates them- 

 selves have. 



After describing and figuring examples of parasitic 

 infection among Infusoria, M. Metschnikoff gives details 

 establishing the important property of " chemiotaxis " — 

 positive and negative— as characteristic of amoeboid 

 protoplasm, selecting the Plasmodium of Mycetozoa for 

 special study. He next discusses the passage from uni- 



