444 



NATURE 



[July 27, 1910 



of zoology in the University of Odessa, and soon 

 afterwards published papers on the embryology of 

 Chelifer and of Myriapods. In the previous year he 

 published an interesting paper on the little nema- 

 tode parasite of fishes' gills— Gyrodactylus — and 

 joined with that fine naturalist, ClaparMe, whom 

 he met at Naples, in a paper on the embryology of 

 Chaetopods. 



After his appointment at Odessa his work was 

 interrupted by the illness and death from tuber- 

 culosis of his first wife, whom he had married in 

 1868. In spite of every care and a long sojourn 

 in Madeira, whither he accompanied her, she died 

 there in 1873. But in 1874 we find a paper by 

 him " On the Eyelids of Mongolians and Cauca- 

 sians," of considerable value to anthropologists, 

 and in 1877 one of a bionomic character on "The 

 Struggle for Existence between Two Species of 

 Cockroaches — PeripJaneta orientalis and Blatta 

 gernianica." 



In 1875 he married his second wife, Olga Belo- 

 coyitoff, who was only seventeen years of age. 

 She had just completed her studies in the " lycee " 

 of Odessa, and attended after her marriage her 

 husband's zoological teaching in the university. 

 She survives him, and was his constant com- 

 panion and ceaselessly devoted friend and help- 

 meet. She often aided him in laboratory work 

 and by her knowledge of English and other 

 languages, though her own special gifts, which 

 she has cultivated to a high degree of excellence, 

 are in painting and sculpture. From time to time 

 she has published her own contributions to sub- 

 jects which were occupying her husband's atten- 

 tion. ^ The earliest of these is one " On the 

 Morphology of the Pelvis and Shoulder-girdle of 

 the Cartilaginous Fishes," published in th; 

 Zeitsch. iviss. Zoologie, 1880. 



Metchnikoff holds an important place beside his 

 great fellow-countryman and intimate friend, 

 Alexander Kowalewsky (who died some years 

 ago), in the establishment of what may be called 

 cellular embryology and the investigation of the 

 early stages of development of invertebrata by fol- 

 lowing out the process of cell-division and the 

 arrangement of the early formed cells in layers. 

 In the twelve years 1875 to 1886, when his last 

 embryological paper was published, he produced 

 many important memoirs on cellular embryology 

 : — namely, on that of calcareous sponges (in which 

 he showed that the inner and outer primitive layers 

 had been transposed in regard to their origin by 

 Haeckel and Miklucko-Macleay) ; on that of 

 jelly-fishes, of Planarians, of Echinoderms, of 

 Ctenophora, and of Medusae. These were accom- 

 panied by important theoretical discussions and 

 suggestions as to the ultimate ancestral origin of 

 the endoderm and the mesoblast. He also wrote 

 on that curious group of minute parasites, the 

 Orthonectids, and on insect diseases. 



But the new departure in his fruitful career was 

 approaching. It grew out of his observations on 

 living jelly-fishes and sponges and on the .trans- 

 parent marine embryos of Echinoderms and the 

 transparent floating mollusc PhyUirhoe. In 1882, 1 

 NO. 2439, VOL. 97] 



owing to political disturbances in the University 

 of Odessa, Metchnikoff migrated to Messina, the 

 harbour of which is celebrated among zoologists 

 for its rich fauna of transparent floating larvee 

 and adjult glass-like Pteropods and jelly-fishes. 

 Here he developed his views, already fore- 

 shadowed in 1880 [Zoolog. Anzeiger), on intra- 

 cellular digestion exhibited by the amoeboid cells 

 of animal organisms, and published a series of; 

 papers in which the name "phagocyte" is first 

 applied to these cells. In this, as in similar cases 

 of discovery, neither Metchnikoff himself nor any 

 of his friends claimed that he was the first to 

 observe all the facts leading to his generalisation^ 

 He was not the first to witness the ingestion of 

 foreign particles, of fragments of dead tissue, and 

 even of bacteria, by the amoeba-like cells of the 

 animal body. He knew and cited the early ob- 

 servations of Haeckel on the ingestion of pigment 

 granules by the amoeboid blood-corpuscles of the 

 sea-slug Tethys. He knew and cited the nume- 

 rous observations on the activity of large amoeboid 

 cells in assisting the resorption or rapid destruc- 

 tion of other tissues in some special instances. 

 He knew the observations of Jeffrey Parker and 

 others on the intra-cellular digestion of food par- 

 ticles taken into their substance by the endoderm 

 cells lining the digestive cavity of Hydra. He 

 knew Koch's observation of bacilli within a 

 colourless vertebrate blood-corpuscle, attributed 

 by that observ^er to the active penetration of the 

 blood-corpuscle by the aggressive bacilli. These 

 and other like instances were all regarded as ex- 

 ceptional by their observers and not interpreted 

 as evidences of a definite and universal activity of 

 the amoeboid cells of large physiological signifi- 

 cance. Metchnikoff was acquainted with the 

 remarkable discoveries of Cohnheim, Strieker, and 

 others (in some of which I had a pupil's share 

 during my stay in the winters of 1869-70 and 

 1870-71 at Vienna and Leipzig respectively). 

 The pathological laboratories were full of observa- 

 tions and talk about the "diapedesis" and "out- 

 wandering " of the amoeboid corpuscles in inflamed 

 tissues, the origin of pus-corpuscles, and the acti- 

 vity of the amoeboid cells in the stellate cavities of i 

 the frog's cornea and other connective tissues 1 

 when stimulated. Metchnikoff put two and two 

 together, and formulated the proposition that in , 

 all multicellular animals the main function of the I 

 cells derived from the deep or mid-embryonic ' 

 layer between the dermal and intestinal lining 

 layers is nutritional, and that they possess the 

 power of ingesting and digesting — as does an 

 amoeba — solid particles, whether such particles 

 are introduced from the outside or are parts of the 

 organism which, owing to one reason or another, 

 must be broken up and removed. The amoeboid 

 cells in connective tissues and in the blood and 

 lymph are such eater-cells or phagocytes, as he 

 now termed them. 



He at once proceeded to explain the significance 

 of these phagocytes and their utility to the organ- 

 ism, not only by pointing to their work as scaven- 

 gers removing injured and dead tissue, to which 



